This replaceable rubber kit for the ZW Field Trialer is easy to employ and always good to have on stock. Zinger Winger suggests to replacing your rubber tubing yearly with normal use. Simply remove pouch from launcher and take off old rubber tubes. Make sure to keep your pulleys and rings because they will be reused. Take the new tubing and loop the end around the ring, securely pinch tubing with two zip ties (included in kit) then trim excess so there is no sharp edges. Make sure to run the pulley on before attaching the other end of the rubber tubing to the pouch. Secure the opposite end of tubing to pouch as you did with the loop ring.