The Vanderbilt and Delray Railing Post Sleeve Kit include the necessary post cap and base trim. Simply slide over your existing treated 4 in. x 4 in. post. And remember to slide the skirt over the post sleeve before installing your railing. Use with the following products (WWR-THDV36-S8, WWR-THDV36-S6, WWR-THDV36-S8S, WWR-THDV36-S6S, WWR-THDV36-C8, WWR-THDV36-C6, WWR-THDV36-C8S, WWR-THDV36-C6S).