We stock many of the O-rings listed in various Coltri part catalogs. Some of the most popular Coltri parts manuals are linked below under the "User Manuals" tab. Several videos are posted under the "Videos" tab also. O-rings are listed by Coltri part number (SKU) with a short description. We cannot except returns on O-rings purchased by customers directly. If you have questions about which O-ring is correct for your specific compressor or component, please contact the sales team for ordering assistance.