Check the listing for details. (3 Pack) Pentair, Pentek 355331 Diffuser O-Ring - Swimming Pool, Pump Oring. Condition: New. Listed at 11.39 USD. (3 Pack) Pentek, Pentair 355331 Diffuser O-Ring - Replacement Specialty Swimming Pool Inground Pump ORing by Captain O-Ring Product Features: Part: Pentair 355331 Diffuser O-Ring Replacement Fits Pentair Challenger high flow/high pressure inground pumps Also compatible with Pentair WaterFall specialty pumps Material: Buna-N (nitrile butadiene rubber) Manufactured and Warrantied by Captain O-Ring LLC, with decades of experience in the sealing and chemical industry. This Pentair 355331 diffuser o-ring is used with Pentair Challenger high flor and high pressure inground pumps. It is also compatible with Pentair WaterFall specialty pumps. O-Ring is 1/8" thick and measures just under 3" inside diameter. What to expect: This item includes three (3) o-rings in a resealable zip-top poly bag with "Captain O-Ring" branded packaging. Manufactured and warrantied against defect for one year by Captain O-Ring LLC. "Captain O-Ring" is a registered trademark of Captain O-Ring LLC.