TonGass (24-Pack, Black) 4"x6" (3 5/8x5 5/8") Wood Fence Post Caps - Wooden Fence Deck Post Covers - Durable Plastic Water-Proof and UV-Proof - Protect Wooden Fence Poles from Cracking and Rotting

For 4 x 6 (3 5/8" x 5 5/8") fence posts - Most 4x6 fence posts actually have nominal dimensions of 3 1/2" by 5 1/2".

Once planed, the side would be around 3 5/8” by 5 5/8" With inside dimensions of 3 5/8" by 5 5/8" and an edge height of 1/2", these black plastic fence post caps will fit perfectly on most fence posts Made from thick, highly durable and weatherproof plastic, our plastic post caps are UV and heat-resentist, impact-resistant and waterproof.

There won't be fading, cracking for years to come The black caps will slip easily on top of the posts.

Even when the post is a few millimeters bigger, the caps will flex enough to fit, but it won't stretch further