Relightable Solar 4 in. x 4 in. Black Vinyl Outdoor Post Cap Deck Lights (4-Pack)Solar 4 in. x 4 in. Black Vinyl Outdoor Post Cap Deck Lights (2 Pack). Will fit within 3 7 8 in. square post. Automatic on off sensor. Solar cap post lights will only fit base within dimension 3 7 8 in. x 3 7 8 in. posts 1 ultra bright white LED with 10 Lumens 4000 to 5000 Kelvin, which lasts up to 100,000 hours Lights up automatically every night auto off switch Weatherproof designed to protect the lights from natural elements, pre installed