The Unicel C-6620 R is a compatible replacement for the following pool and spa filter cartridges:
The Unicel C-6620 Comp. Pool & Spa Water Filter is constructed with 20 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-3840, measures 6 1/4" in diameter and 8" in length with 2 3/8" Open top and bottom styles. This compatible Unicel pool filter also features antimicrobial end caps and wider support bands.