Check the listing for details. Replacement 3M 63597174C, AO-WH-STD-OR-2, ORG006, WP252235 O-Rings (3 Pack). Condition: New. Listed at 11.69 USD. Replacement 3M 63597174C, AO-WH-STD-OR-2, ORG006, WP252235 O-Rings (3 Pack) Product Features: These replacement 3M Aqua Pure 63597174C o-rings also go by part numbers 3M Aqua-Pure 63597174P, AquaPure ORG006, Watts WP252235, AO Smith AO-WH-STD-OR-2, and Project Source PS-WHS-ORG. Compatible with the following water filter housings:3M (AquaPure): AP11S, AP11T, AP12S, AP12T, AP26T, AP51T, AP101S, AP101T, AP102S, AP102T, AP110, FHO-34, FHT-343M AP200/210 Series, APC77, APC78, APCRF (Replaces square ring 36851-35)AO Smith AO-WH-PRE, AO-WH-PREV, AO-MF-BProject Source PS-WHS-H, PS-WHS-HVWatts: 500222, 500223 It is recommended to replace the o-ring with every 3rd filter change to prevent leaks. Includes three (3) O-Rings in a resealable zip-top poly bag with "Captain O-Ring" branded packaging. Molded from NSF 61 certified buna-n rubber for safe and clean drinking water. Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA!