The Compression Coupling 600 Series creates a watertight connection in supply tubing or dripline (0.610 in. to 0.640 in. OD). Tubing is inserted into the compression ring, where an internal barb compresses the tube and holds it in place. This compression fitting is made of ABS plastic treated with UV inhibitors to prevent fading and cracking. Use fittings to set up a new drip irrigation system, expand an existing system, or make repairs.