Fit for 4x4 Wooden & 4x4 5x5 Vinyl Posts:Designed for fence posts, deck railings, and pillars, these solar post cap lights fit standard 4x4 wooden(actual 3.5x3.5 inches) & 4x4,5x5 vinyl posts(actual 4x4,5x5 inches), enhancing safety and aesthetics in your yard, driveway, or porch 2 Lighting Modes & Auto On/Off:Easily switch between warm white and cool white with the 2 lighting modes to create the perfect ambiance.The built-in light sensor ensures the fence post solar lights automatically turn on at dusk and off at dawn for effortless outdoor lighting