4 Pack Solar Powered Black Outdoor Garden Post Cap Light for 4x4 PVC Posts Smooth & durable weather resistant surface is perfect for handling the natural elements Brilliant white LED bulb has a life expectancy of over 100,000 hours Each light includes a 600mAh AA Ni-Cd battery that's recharged by the natural power of the sun 100% solar powered; no external wiring necessary Product Dimensions - 5.75" x 5.75" x 4.5", Base Dimensions: 4" x 4" Post Size Fitting; these post caps will ONLY fit on 4" x 4" Vinyl, PVC or Plastic posts. The opening on the bottom of the post cap which fits over the top of the post is exactly 4 1/16" x 4 1/16". *** This post cap is not designed for use on Wooden posts!