As wonderful as the Game Ready therapy system is, just like every other mechanical item, parts can break down over time. That includes the O-rings that are part of the Game Ready Control Unit. Eventually the rubber O-rings used at all the hose connections will need to be replaced. Over time, as rubber does, the O-rings may swell, crack, rot, harden or otherwise degrade. A problem will be noticed when the unit starts having issues with leakage, difficulty in plugging the hose into the control unit, certain error codes appear, etc. If hardening is the issue, a little silicone spray (available separately) to lubricate might solve the problem. If not, this kit which has 9 Replacement O-rings, is here. To replace, gently remove the damaged O-ring being careful not to scratch the metal connector. Replace with a new-O-ring and carefully secure it in place, being sure not to over-stretch or twist the O-ring. Work is done when the O-ring is secure 360 degrees in the groove. Please note, this is the Panel Mount O-Ring Replacement Kit Only. Game Ready wraps, control unit, hoses and all other accessories are available separately. If unsure if the O-ring should be replaced, try a little silicon spray first to see if that resolves the issue. Replacing the O-ring, while not overtly complicated, does requires some basic mechanical "do-it-yourself" skills and a comfort level working with tools. Users may find it helpful to work with a tool to help remove stubborn O-rings or securely and properly place the new ones. When using a tool, users must be careful not to scratch the metal connector. Before work starts on replacing O-rings, ensure the Game Ready unit is turned off and unplugged. Users should never do mechanical work on the unit with it plugged in. This O-Ring Replacement Kit is applicable to all Game Ready systems.