O-Rings for Big Blue 10x5 and 20x5 inch Water Filter Housings that accomodate 4.5 to 5 inch wide water filters. ACTUAL diameter 5.5". A set of 3 orings. Actual Diameter: 5.465 inch (inside diameter) or 139 mm. Black orings. Material: Buna-N Rubber.
The most common o rings ( also called oring , rubber gasket , o-rings, rubber seals ) used in water filtration are made from Buna N material. Buna N is also commonly referred to as nitrile. This is the ideal choice for cold water filtration because they are inexpensive and have superior performance characteristics.
Typical housing for these o-rings is blue (blue with blue cap, blue with black cap) outside dimentions for the housing can be 12x7 or 23x7. Measure actual o-ring diameter for better match.
Please choose "Crystal Quest" if your system is Crystal Quest, for all other Big Blue housings, including standard and Pentek housings, use "Pentek".
Actual Diameter: 5.5" or 139 mm.