Key Features Used on cookers and canners built prior to 1977 Allows excess steam to escape Allows excess steam to escape. Used on models manufactured before 1977. Not for use with pressure cookers or canners manufactured since 1977 which contain a combination air vent/cover lock. Fits presto pressure cooker models: 01/pca4, 01/pca6, 01/pcc4, 01/pcc4a, 01/pcc4d, 01/pcc4h, 01/pcc6, 01/pcc6a, 01/pcc6ad, 01/pcc6d, 01/pcc6h, 01/pcc6hd, 01/pcd4, 01/pcd4h, 01/pce4, 01/pce4a, 01/pce4h, 01/pce6, 01/pce6a, 01/pce6h, 01/pcs4, 01/pcs6, 02/pca4, 02/pca4h, 02/pca6, 02/pca6h, 02/pce6h, 02/pcs4, 02/pcs6, 103, 104, 106, 204, 206, 40 (2 1/2qt), 40 (4-qt), 40 (6-qt), 403, 404, 406, 50, 60 (2 1/2-qt), 60 (4-qt), 603(us), 603(can), 604, 700 (3-qt), 700 (4-qt), 700 (6-qt), 703, 704, 706, 733, 744, 803b, 804, 804b, 833, a401, a403a, a403ad, a403at, a409, a410a, a411a, a412a, a413a, a414a, a415a, a416a, a601, a603a, a603ad, a603at, a607a, a608a, a609a, a610a, a611a, a612a, a613a, a614a, a615a, a616a, a617a, a618a, a619a, a620a, a621a, a622a, a623a, b301a, b301b, b302a, b401a, b401b, b403a, b601a, b602a, b604a, b605a, c301a, c301b, c401a, c401b, c601a, c603a, ke02a, ke02at, ke03a, ke03at, pb01a, pb02a, pb05a, pb06a, pb07a, pb08a, pb09a, pb10a, pb11a, s-60, s-66, sc-35 fits presto pressure canner models: 01/ca16a, 01/ca16h, 01/ca21a, 01/ca21h, 01/caa12h, 01/caa20h, 02/caa12h, 02/caa16h, 02/caa20h, 21, 21av, 21b, 21s, 5, 7, 7av, 7b, 7s, ca16, ca16h, ca21, ca21h
