Unicel 8CH-502 and Filbur PVT50WH-F2L Compatible Spa Cartridge Filter
The pool and spa filter that replaces both Unicel 8CH-502 and Filbur PVT50WH-F2L filter cartridges has a closed top with a little handle as well as a threaded bottom connector.
The actual size is 7 1/4″ x 8×5″ ( 18.4 x 21.6cm )
This filter type used in select model Vita Spas. 50sqft cartridge filter for hot tubs.