OR-241-S Pentek O-Ring

The rubber O-ring provides the water-tight seal between the cap and the bottom of the housing. The PENTEK-OR-241-S O-ring should be lubricated with clean silicone grease and placed in the groove below the threads of the housing to prevent a water leak. O-rings do not last forever and should be replaced any time you change the filter cartridge. The OR-241-S is an inexpensive part of your filter system and helps protect you from water damage due to a leaky seal between the housing and cap.