The Unicel C-5431 R is a compatible replacement for the following pool and spa filter cartridges:
The Unicel C-5431 Comp. Watkins 30 Pool Water Filter is constructed with 30 sq. ft. of premium media area and sharp pleat folds to capture contaminants in your swimming pool and spa water. This pool filter cartridge, also known as the Filbur FC-3910, measures 5 1/8" in diameter and 10 1/4" in length with a 1 5/8" Open top style and 1 9/10" Open bottom style with Slots. This compatible Unicel pool filter also features antimicrobial end caps and wider support bands.