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Lot of 16 Outdoor Deco Solar Rock Spot Light 3 LEDs |  |
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US $114.99 | 1d 19h 41m |
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16 Large Outdoor Garden AA Solar Rock Spot Light 3 LED | |
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US $114.99 | 1d 21h 11m |
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Wall Mount Solar Spot Light Ultra Bright 4 LED set of 12 | |
0 Bid | US $185.00 | 2d 4h 57m |
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MOTION DETECTION Solar Power SPOT LIGHT ILLUMINATION 30 | |
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US $119.99 | 2d 18h 22m |
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8 Pack Pacific Solar™ Outdoor Garden Decor Solar Rock Spotlight Light FREE SHIP | |
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US $109.88 | 2d 19h 20m |
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4 PACK Outdoor Ultra Bright 6 LED Accent Solar Spot Light Metal Body ST238 4pk | |
0 Bid | US $119.95 | 2d 19h 44m |
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12 PACK Pacific Solar™ Outdoor Garden Solar Rock Spot Light 3 LEDs Patio Lights | |
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US $134.48 | 2d 21h 10m |
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12 Pack Pacific Solar Outdoor Garden Decor Solar Rock Spotlight Light FREE SHIP | |
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US $134.88 | 2d 21h 15m |
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4 PACK FREE SHIP Outdoor Ultra Bright 6 LED Accent Solar Spot Light Metal Body | |
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US $109.70 | 3d |
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12 Pack Atlantic Solar Stainless Steel Landscape Light Spotlight FREE SHIP | |
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US $129.70 | 3d 31m |
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8 PACK Pacific Solar Outdoor Garden Decor Solar Rock Spot Light FREE SHIP | |
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US $119.97 | 3d 1h 47m |
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NEW 4 SETS12 MALIBU SOLAR SPOT LIGHTS LZ413 | |
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US $142.00 | 4d 6h 13m |
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Garden 12 Inch Multi Spot Solar Light VSE02147 X72 | |
0 Bid | US $269.99 | 4d 18h 46m |
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8 PK FREE SHIPPING Outdoor Ultra Bright Accent Solar Lights Spot Light Metal | |
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US $189.70 | 4d 19h 24m |
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12 PK FREE SHIPPING Outdoor Ultra Bright Accent Solar Lights Spot Light Metal | |
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US $268.70 | 4d 19h 29m |
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8 PACK Solar Spot Light Ultra Bright 4 Super Bright LED Spotlights FREE SHIPPING | |
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US $157.80 | 5d 20h 11m |
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12 Pk FREE SHIP Solar Powered Light Outdoor Brown Boulder Rock Spotlight Lights | |
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US $128.49 | 5d 21h 53m |
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High Intensity Solar LED Spot light for pond landscape water garden submersible | |
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US $198.75 | 7d 22h 1m |
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Jen TIKI With LED Solar Spot Light H 42 x D 10 | |
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US $179.00 | 8d 12h |
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Solar Powered LED Spot Lights Set of 6 | |
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US $141.38 | 8d 13h 40m |
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TEN 12V LED Light Lamp Spot Globe Torch E27 800lm Solar | |
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US $103.50 | 9d 11h 50m |
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12 Pack Stainless Steel Solar Powered Spotlight ST 237 | |
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US $134.50 | 10d 13h 51m |
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TEN 12V 3W LED Spot Narrow Light E27 Solar Panel Marine ES Socket Fitting BRIGHT | |
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US $103.50 | 11d 11h 14m |
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6 Ultra Bright Solar Garden Spot Adjustable Light 6 LED | |
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US $119.99 | 11d 18h 28m |
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18 x Garden Solar Spot Adjustable Light Lamp 3 LED | |
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US $119.99 | 12d 17h 58m |
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Vintage Solar Model 656 Badger Brass MfgCo Headlamp car motorcycle old 1910 era | |
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US $425.00 | 13d 15h 39m |
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6 X Ultra Bright Metal Solar Spot Light w 6 Bright LED Garden Landscape Lawn | |
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US $119.99 | 13d 16h 8m |
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Early 50s Boat SearchLight Projector Spotlight Chrome SOLAR Model 768B | |
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US $199.99 | 14d 16h 28m |
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SOLAR security POWERED 54LED 10W Flood spot light | |
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US $202.09 | 16d 4h 11m |
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Set of 6 Bright 4 Light LED Solar Spot Lights for Outdoor Garden Patio Lighting | |
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US $111.50 | 16d 16h 25m |
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16 of Outdoor Solar Power Rock Stone Spot Light 3 LED | |
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US $124.99 | 16d 20h 38m |
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TEN 12V 3W LED Spot Down Light Bulb Lamp PV Solar Panel | |
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US $110.09 | 17d 3h 37m |
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TEN 12V 3W LED Spot Down Light Bulb Lamp PV Solar Panel MR16 ES27 Edison Socket | |
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US $103.98 | 17d 4h 1m |
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12 Pack Stainless Steel Solar Powered Spotlight St 237 | |
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US $132.95 | 17d 16h 47m |
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MOTION DETECTOR HALOGEN SPOTLIGHT SOLAR POWERED 8 HRS | |
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US $119.99 | 20d 9h 57m |
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45 LED | SPOT | FLOOD LIGHTS | SOLAR | SIGN LIGHT | LED | |
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US $385.00 | 21d 19h 36m |
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16 Outdoor Deco Solar Stone Rock Spot Light 3 LEDs | |
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US $124.99 | 23d 19h 43m |
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SOLAR POWERED Security 54LED Flood spot light 10W solar panel EMS shipping | |
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US $197.39 | 24d 6h 38m |
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Wall Mount Solar Spot Light Ultra Bright 4 LED Set 12 | |
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US $140.00 | 26d 6h 23m |
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8 PACK Solar Wall Mounted Lamp Light Outdoor Spot Floodlight FREE SHIPPING | |
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US $128.90 | 27d 9h 42m |
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36W Pure White E40 LED Street Light Solar System Park Road Lamp 110V 240V spot | |
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US $138.05 | 28d 19h 8m |
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16 Pack Atlantic Solar Stainless Steel Landscape Light Spotlight FREE SHIP | |
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US $169.70 | 29d 18h 13m |
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12 PACK Solar Spot Light Ultra Bright 4 Super Bright Spotlights FREE SHIPPING | |
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US $217.40 | 29d 19h |
Znamya 2 calculation?
The Russian Znamya 2 was a 20-meter wide (flat) mirror, launched in 1992. It was
designed to test the feasibility of illuminating parts of the Earth’s surface by reflecting
sunlight from orbiting mirrors. Znamya 2 was deployed (for a few hours only) near
the space station MIR, orbiting at an altitude of
∼ 390 km.
(a) Calculate what size spot on the Earths surface was illuminated by Znamya 2.
(b) Assuming the mirror was optimally positioned so that it was
∼ perpendicular to
light from the Sun, how much solar energy did it receive per second ?
The Sun is about 1/2 degree wide in the sky, so the cone of light cast by an infinitely small mirror would be 1/2 degree wide or 390km * Tan 0.5 degree = 3.4 kilometer wide spot on the ground. So the 20 meter wide mirror make a spot 3.4 km + 20 meters wide, or 3.42 km wide. The area would be about 9,186,331 square meters, or almost 30,000 times larger in area than the 314 square meters area of the 20 meter mirror (assuming it is round). So the sunlight would be 30,000 times less intense than direct sunlight.
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Lot of 16 Outdoor Deco Solar Rock Spot Light 3 LEDs | |
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US $114.99 | 1d 19h 41m |
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16 Large Outdoor Garden AA Solar Rock Spot Light 3 LED | |
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US $114.99 | 1d 21h 11m |
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Wall Mount Solar Spot Light Ultra Bright 4 LED set of 12 | |
0 Bid | US $185.00 | 2d 4h 57m |
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MOTION DETECTION Solar Power SPOT LIGHT ILLUMINATION 30 | |
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US $119.99 | 2d 18h 22m |
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8 Pack Pacific Solar™ Outdoor Garden Decor Solar Rock Spotlight Light FREE SHIP | |
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US $109.88 | 2d 19h 20m |
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4 PACK Outdoor Ultra Bright 6 LED Accent Solar Spot Light Metal Body ST238 4pk | |
0 Bid | US $119.95 | 2d 19h 44m |
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12 PACK Pacific Solar™ Outdoor Garden Solar Rock Spot Light 3 LEDs Patio Lights | |
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US $134.48 | 2d 21h 10m |
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12 Pack Pacific Solar Outdoor Garden Decor Solar Rock Spotlight Light FREE SHIP | |
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US $134.88 | 2d 21h 15m |
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4 PACK FREE SHIP Outdoor Ultra Bright 6 LED Accent Solar Spot Light Metal Body | |
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US $109.70 | 3d |
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12 Pack Atlantic Solar Stainless Steel Landscape Light Spotlight FREE SHIP | |
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US $129.70 | 3d 31m |
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8 PACK Pacific Solar Outdoor Garden Decor Solar Rock Spot Light FREE SHIP | |
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US $119.97 | 3d 1h 47m |
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NEW 4 SETS12 MALIBU SOLAR SPOT LIGHTS LZ413 | |
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US $142.00 | 4d 6h 13m |
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Garden 12 Inch Multi Spot Solar Light VSE02147 X72 | |
0 Bid | US $269.99 | 4d 18h 46m |
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8 PK FREE SHIPPING Outdoor Ultra Bright Accent Solar Lights Spot Light Metal | |
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US $189.70 | 4d 19h 24m |
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12 PK FREE SHIPPING Outdoor Ultra Bright Accent Solar Lights Spot Light Metal | |
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US $268.70 | 4d 19h 29m |
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8 PACK Solar Spot Light Ultra Bright 4 Super Bright LED Spotlights FREE SHIPPING | |
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US $157.80 | 5d 20h 11m |
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12 Pk FREE SHIP Solar Powered Light Outdoor Brown Boulder Rock Spotlight Lights | |
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US $128.49 | 5d 21h 53m |
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High Intensity Solar LED Spot light for pond landscape water garden submersible | |
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US $198.75 | 7d 22h 1m |
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Jen TIKI With LED Solar Spot Light H 42 x D 10 | |
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US $179.00 | 8d 12h |
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Solar Powered LED Spot Lights Set of 6 | |
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US $141.38 | 8d 13h 40m |
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TEN 12V LED Light Lamp Spot Globe Torch E27 800lm Solar | |
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US $103.50 | 9d 11h 50m |
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12 Pack Stainless Steel Solar Powered Spotlight ST 237 | |
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US $134.50 | 10d 13h 51m |
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TEN 12V 3W LED Spot Narrow Light E27 Solar Panel Marine ES Socket Fitting BRIGHT | |
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US $103.50 | 11d 11h 14m |
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6 Ultra Bright Solar Garden Spot Adjustable Light 6 LED | |
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US $119.99 | 11d 18h 28m |
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18 x Garden Solar Spot Adjustable Light Lamp 3 LED | |
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US $119.99 | 12d 17h 58m |
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Vintage Solar Model 656 Badger Brass MfgCo Headlamp car motorcycle old 1910 era | |
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US $425.00 | 13d 15h 39m |
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6 X Ultra Bright Metal Solar Spot Light w 6 Bright LED Garden Landscape Lawn | |
|
US $119.99 | 13d 16h 8m |
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Early 50s Boat SearchLight Projector Spotlight Chrome SOLAR Model 768B | |
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US $199.99 | 14d 16h 28m |
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SOLAR security POWERED 54LED 10W Flood spot light | |
|
US $202.09 | 16d 4h 11m |
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Set of 6 Bright 4 Light LED Solar Spot Lights for Outdoor Garden Patio Lighting | |
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US $111.50 | 16d 16h 25m |
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16 of Outdoor Solar Power Rock Stone Spot Light 3 LED | |
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US $124.99 | 16d 20h 38m |
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TEN 12V 3W LED Spot Down Light Bulb Lamp PV Solar Panel | |
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US $110.09 | 17d 3h 37m |
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TEN 12V 3W LED Spot Down Light Bulb Lamp PV Solar Panel MR16 ES27 Edison Socket | |
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US $103.98 | 17d 4h 1m |
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12 Pack Stainless Steel Solar Powered Spotlight St 237 | |
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US $132.95 | 17d 16h 47m |
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MOTION DETECTOR HALOGEN SPOTLIGHT SOLAR POWERED 8 HRS | |
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US $119.99 | 20d 9h 57m |
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45 LED | SPOT | FLOOD LIGHTS | SOLAR | SIGN LIGHT | LED | |
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US $385.00 | 21d 19h 36m |
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16 Outdoor Deco Solar Stone Rock Spot Light 3 LEDs | |
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US $124.99 | 23d 19h 43m |
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Mr Beams MB360 Wireless LED Spotlight with Motion Sensor and Photocell - Weatherproof - Battery Operated - 140 Lumens List Price: $24.99 Sale Price: $19.41  |
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Dorcy 41-1071 LED Wireless Motion Sensor Flood Lite List Price: $24.99 Sale Price: $18.74 Used From: $18.13 |
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10 LED Wireless Motion Sensor Light - 2 Pack List Price: $19.95 Sale Price: $16.20 |
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Instantly add motion-activated light for security and safety - indoors or out*Infrared technology senses both movement and heat for fewer false activations; daylight-off function*Compact (3 in. x 3 in... |
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Goal0 14001 3-Watt Estrella Light List Price: $59.99 Sale Price: $34.00 |
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Goal Zero Estrella 3W Light - Goal Zero GZ-14001. |
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110 V 21 LED E27 Solar Halogen Marine Spot Light Bulb Sale Price: $1.99 |
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Package Includes: 1 x 110 V 21 LED E27 Solar Halogen Marine Spot Light Bulb(Bulb) |
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High Power 80 Lumen MR16 GU5.3 Base Single LED 30 Deg. Spot Light 12v Bulb, 1204wh Sale Price: $19.50 |
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Solar Floodlight List Price: $80.00 Sale Price: Too low to display |
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Lighten up! Solar Floodlight for a shine anywhere! PRICED LESS! A brilliant, free-powered, no-wiring Light to brighten a flag, walkway, sign, landscape, shed... whatever you point it at! Here's the way to go with the glow: The 6" square solar panel generates the power, no external electricity... |
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Energizer Solar SOLRECBP Spot Light. ENERGIZER SOLAR SPOTLIGHT SOLAR OR CAR ADAPTER PERS. LED List Price: $58.97 Sale Price: $34.69 |
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Energizer Solar SOLRECBP Spot Light. ENERGIZER SOLAR SPOTLIGHT SOLAR OR CAR ADAPTER PERS. LED |
