LA Spas Aqua Kleen replacement filter socks and cartridges. The Filter Sock & Frame can be replaced with the LA Spas 45/85 replacement cartridge listed below. 

Common Cartridge Filter Dimensions:
Length: 178mm
Width: 133mm
Spigot: 69mm
or
Length: 200mm
Width: 127mm
Spigot: 69mm

Some other sizes have been sold, but all are interchangeable.