These 1 3/8" x 1 3/8" Coupler sleeves allow the joining of two pieces of pipe together, in a simple and easy way. The couplers are extremely durable, easy-to-use and form a long-lasting connection. They fit two 1 3/8" pipe - one inserted into each end of the sleeve. Once in place, they form a rigid, sturdy bond. They can be used to put top rails onto fence kits and for DIY enclosure connection.