Secure two sections of 17mm supply tubing or dripline, or branch 17mm supply tubing from a 1/2 in., 3/4 in., or 1 in. main line with the 17mm Insert Barb Coupling. Coupler fits inside 17mm drip tubing or 17mm dripline and anchors into place. Micro fitting is made of acetal 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.