After rebuild, these will normally last up to 10,000 -15,000 hours before the cup seal needs to be replaced again! We are a business and closed Weekends. Looking for a kit for a different model - just ask - we carry a full line of new pumps and rebuild kits for ALL Thomas, Matala, Kasco, Jenny, Welch, GSE, Gast, and many other Compressors. Thousands of kits available - Thousands of NEW Pumps available!