• Weight: 3 oz. 

• Width: 6 1/4" 

• Length: 8" 

• Area: 20 sq. ft. 

• Top Style: 2 3/8" Open 

• Bottom Style: 2 3/8" Open 

The Unicel C-6620 R Compatible Pool & Spa Replacement Filter Cartridge is a spa or swimming pool filter cartridge for the Muskin 20. The Filbur FC-3840 is a compatible replacement filter. These pool or spa filters feature an open PVC-enforced core measuring 2 3/8 inches in diameter and cover a filtration surface area of 20 square feet. The FC-3840 spa filter cartridges are able to replace the following manufacturer part numbers: Muskin A3821, FD-20, FD-40, and FE-20, Unicel C-6620, Pleatco PMS10-4/PMS20-4, and Aladdin 12002.