Moen has a lifetime guarantee. After trying to reach Moen via phone on a Tuesday, the automated message said that I could schedule a call back from customer service on Thursday, Friday or the following Tuesday. The automated message also said if I was checking on the status of an order, allow 10 business days before calling. This being unacceptable, I ordered the O-ring and cartridge kit late Thursday from Chicago Faucet Shoppe and had them Sunday. Both parts were as advertised and installed easily. My first time dealing with Chicago Faucet Shoppe and I was very impressed. Customer Service was good and order was received promptly and accurately. Will be using Chicago Faucet Shoppe for my future needs! Thanks!