This solar post caps fit exactly with 4×4 (actual size 3.5"x3.5") wood post. Solar deck post lights comes with a metal bracket, which also can install on 5X5 6X6 wood posts or platforms ( If your posts actual size larger than 3.5", the wood will exposed, please buy with caution). Please watch the video for different size posts installation! Inside diameter of post cap measures: 3.6 x 3.6 inches. Note: These are not for pvc post and vinyl post.
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