The sealing ring fits around the inside rim of the cover and forms a pressure-tight seal between the cover and the body of the pressure canner during canning and cooking. When installing a sealing ring, work it into the cover in four small sections, for example, top, bottom , left and right. Work it into the groove a small section at a time until it is fully in place. Place the cover on the cooker body. Put one hand on the top center of the cover and push down firmly. Open and close the cover several times. Fits Presto pressure canner models 01/CAA12H 02/CAA12H 01/C13 0171001 0171002 0171003 02/CAA16H 01/C17 0174001 0175001 0175005 0175006 0175002 0175003 0175004 01/CAA20H 02/CAA20H 01/C22 0177001 01/CG22 0178001 0178005 0178006 0178002 0178003 0178004