The Pentair 350013 Lid O-Ring (3 pack) fits Pentair IntelliFlo VF, VS 3050, VS-SVRS; WhisperFlo; Challenger; and Pinnacle inground pool/spa pumps. It is also compatible with EQ-Series commercial and WaterFall pool/spa pumps. See parts diagram in product photos for how this o-ring fits into your pump. The 350013 o-ring has an inside diameter of just under 5-7/8" and outside diameter of about 6-1/4”. This o-ring's thickness is slightly larger than 1/4”. --- Only purchase this item if your water system calls for Part Number 350013. Please contact Captain O-Ring LLC if you are unsure if this is compatible with your unit. 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.