Spa Filter Baleen: AK-6021, OEM: 57005700,R173201, Pleatco: PCM25 , Unicel: C-7425 , Filbur: FC-0615, Diameter: 7", Length: 9-13/16"

Filter Specifications:

• Square Footage: 25 sq. ft.
• Media/Thickness: 4
• Diameter: 7"
• Length: 9-13/16"
• Top: 3" Hole
• Bottom: 3" Hole

Equivalent to:

• Pleatco: PCM25
• Unicel: C-7425
• Filbur: FC-0615
• OEM: 57005700,R173201

This Filter Fits The Following Brands:

Pentair American Products, Hayward

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