These are specially designed fence kits that include protection against climbing animals (keeps animals in, keeps animals out or keeps animals both ways in and out). The posts in these kits include extensions on the top of each post; when paired with included fencing, these extensions make an overhead canopy that animals can't climb over. These kits can include overlap on the ground and also a snake barrier at the bottom. They are most often used by customers that want to keep their cats in and other animals out (like snakes) but also want to keep out other climbing animals like raccoons.