Product Details
•     Model Name: RD50 Spa Cartridge Filter
•     Filtration Area: 50 square feet
•     Dimensions:
•     Length: 339mm
•     Outer Diameter: 126mm
•     Hole Diameter (Top & Bottom): 54mm
•     Connection Type: Suits top-load and in-line filter housings
•     Compatibility: The RD50 filter suits spas that use the following systems and brands:

• Leisurerite Spas
• Rainbow Dynamic RDC50 filter housings
• Waterco Top Load filter systems
•  Waterway Plastics top-load and in-line filters
• Pentair / Rainbow spa systems
• Viking Spas
• Spaquip / Davey systems (select models)
• Chinese-manufactured spas using 339mm x 126mm filters

•     Generic top-load filter housings with 54mm internal hole
•     Common across many spa brands for over 15 years
•     Material: Pleated fabric for high-efficiency filtration
•     Installation: Drop-in replacement; no tools required
•     Alternate Codes: FC-FAA309, PWW50L, 4CH-949, FC-0172
•     Common Use: Spa and hot tub water filtration
•     Note: Do not confuse with RDC25 (25 Sq Ft version with similar appearance)