Culligan 3/4" Housing O-Ring. It is used to help ensure the seal of the water filtration system. It is for use with water filter system TV# 216912. Replacement O-ring seal for use with the Culligan WH-S200-C. Ensures the seal of the water filtration system. The O-ring is used to seal the housing canister to the housing cap to prevent leaks. Replace your O-ring every third filter change or when there is damage to prevent leaks. It is easy to use and commonly used with Culligan WH-S200-C (Ace #4867560). Make sure to use a food grade lubricant on the O-ring when replacing. Its flexibility and tear resistance ensure long lasting use.