The Northwest 5x13 R is a compatible replacement for the following pool filter cartridges:
The Northwest Spas Comp. Pool Filter Replacement is a pool water filter constructed with a media area of 50 square feet and weight of 3 oz. This compatible Northwest Spas filter cartridge measures 4 15/16" in diameter and 13 5/16" in length and is manufactured with Open 2 1/8" top/bottom styles. This spa filter replacement improves swimming pool/spa water clarity and quality.