CHEEKON 3.5 or 4 x 4 Solar Post Cap Lights, Metal and Glasses, Bronze, Wood Post Fence Post Cap Outdoor Garden Yard Deck Street Top Wall (3.5 or 4 x 4) COMPATIBLE - FITS to any standard 4"x4" wood post , Opening size : 3.5 inches . SOLAR POWERED - these post cap lights utilize the free natural power of the sun to operate. A silicon solar panels absorb light during the day and recharge the Ni-MH battery (included) for use in the dark eliminating your need to swap out batteries or install a costly outdoor power system . SOLAR POWERED - these post cap lights utilize the free natural power of the sun to operate. A silicon solar panels absorb light during the day and recharge the Ni-MH battery (included) for use in the dark eliminating your need to swap out batteries or install a costly outdoor power system . ENERGY efficient LED - LED provides brighter glow for better visibility. DURABLE - CHEEKON company takes pride in providing some of the higher quality products in the solar industry. These lights are features a metal and glass, that have been designed to handle the outdoor elements for years to come.