The 17mm Insert Barb Ball Valve controls the flow of water using a rotary ball. Valve has a dial on top that moves the ball with drilled hole, rotating the ball to allow water to flow through the hole or closing off the channel to prevent water flow. The barbed ends on either side fit into 17mm drip tubing or 17mm dripline and anchors into place. This insert barb 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.