Spa Filter Darlly: 40503 Baleen: AK-9007, Darlly: 40503 OEM: 1561-05, Pleatco: PTL50P4-4 , Unicel: 4CH-50 , Filbur: FC-0151, Diameter: 4-5/8", Length: 14-3/4"

Filter Specifications:

• Square Footage: 50 sq. ft.
• Media/Thickness: 4
• Diameter: 4-5/8"
• Length: 14-3/4"
• Top: Handle
• Bottom: 1-1/2" MPT

Equivalent to:

• Pleatco: PTL50P4-4
• Darlly: 40503
• Unicel: 4CH-50
• Filbur: FC-0151
• OEM: 1561-05, 6540-486

This Filter Fits The Following Brands:

LA Spas, Nemco, Dimension One, Advanced Spa Design

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