These robust Outdoor Essentials® 4 in. x 4 in. x 8 ft. Evanston vinyl picket fence Corner Posts were designed to be used with Pro Series 6 ft. Evanston Spaced Picket Fence Panels and 6x4 gates. These posts have routed holes to accept the 3 fence rails. The rails from the fence slide into the routed holes in these posts and lock into place for an easy, fastener-free post-to-rail connection. Routed holes are on adjacent sides of the post to connect fence sections at a corner. Outdoor Essentials posts are made of the same durable vinyl as their fence panels and gates. These posts are structural and do not need to be sleeved over a 4x4 wood post during installation.