The DeckoRail 4 in. x 4 in. Solar Post Cap, with its black antique design, adds beauty and distinction to your deck, fence and sign projects. By night, the post cap emits a pleasant glow to enhance your outdoor living space. The post cap fits standard 4 in. x 4 in. wood posts and is easy to install. And, you won’t need to install additional wiring for the solar-powered light. Rechargeable batteries are included.