These energy efficient and low maintenance premium Atlantic Solars™ lights are brand new in their original retail packaging. During the day, the solar lights’ panels harness the power of the sunlight to charge the internal Lithium Ion battery. At night they automatically turn on, emitting a bright light for your fence post line. One Pre-Installed Exceptional 3.2V Lithium-Ion Battery Per Unit, LED: 5 Ultra Bright White Can Last Up To 100,000 Hours Solar panel: New & Improved For Superior Charging Material: Premium Heat Resistant Plastic Operating Time: Up to 10 hours (depending on the regions, weather and sunlight availability) Safe & Water Resistance, Wireless Overall dimensions : 5.4″ (L) X 5.4″ (W) X 3.5″ (H) Mounting Base (Inside Diameter): 4 1/16″ X 4 1/16″ (fit all 4×4 Hollow PVC/Vinyl/Plastic Post)