Spa Filter Darlly: 50251 Baleen: AK-4028, OEM: 42-2891-08-R, Pleatco: PJ25-IN-4 , Unicel: C-5625 , Filbur: FC-1425, Diameter: 5", Length: 13"

Filter Specifications:

• Square Footage: 25 sq. ft.
• Media/Thickness: 4
• Diameter: 5"
• Length: 13"
• Top: 2-3/8" Hole
• Bottom: 2-3/8" Hole

Equivalent to:

• Pleatco: PJ25-IN-4
• Darlly: 50251 
• Unicel: C-5625
• Filbur: FC-1425
• OEM: 42-2891-08-R

This Filter Fits The Following Brands:

Jacuzzi CFR-25/CFT-25, Cantar, Atlantic

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