Spa Filter Baleen: AK-90031, OEM: FF-150, Pleatco: PFF25P4 , Unicel: 4CH-22 , Filbur: FC-2399, Diameter: 4-15/16", Length: 6-5/8"

Filter Specifications:

• Square Footage: 25 sq. ft.
• Media/Thickness: 3
• Diameter: 4-15/16"
• Length: 6-5/8"
• Top: 2 1/8" Hole
• Bottom: 1-1/2" MPT

Equivalent to:

• Pleatco: PFF25P4
• Unicel: 4CH-22
• Filbur: FC-2399
• OEM: FF-150

This Filter Fits The Following Brands:

Freeflow Spas CLX, Tempest, Lagos

Filter Glossary

As you can see in this graphic, when looking at a filter's threads from the side the difference is very obvious. Standard, sometimes called "MPT" or "Male Pipe" threads are smaller and have a higher number of threads than the S.A.E. style. The S.A.E. threads are large and are square in nature almost resembling a child's toy.

• MPT: Male Pipe Thread
• FPT: Female Pipe Thread

How to measure a hot tub filter references:

Spa Care Center or Pool Care Center