The Muskin A3816 R is a compatible replacement for the following spa filters:
The Muskin A3816 Comp. Pool & Spa Filter Cartridge is a spa filter cartridge that measures 6 1/4" in diameter x 8" in length with 2 3/8" Open top & bottom styles. This compatible Muskin Spas filter purifies swimming pool and spa water through 16 sq. ft. of media area.