Applicable Sizes: Our solar post cap lights fit 3.5"x3.5", 4"x4" and 5"x5" wooden or vinyl deck and fence posts. Each one comes with 2 additional removable adapter base sizes for an ideal fit. Install in 1 minute flat with screws provided. 2 Light Modes - Warm/Cool White: Switch effortlessly between cozy sunset-inspired warm glow and crisp cool white light. Perfect for your posts, fence, deck, patio, garden, porch, and mailbox. (Note: Before use, slide the switch to warm light or white light.)