Spa Filter Darlly: 40351, Baleen: AK-9006, OEM: 6540-486, Pleatco: PTL35P4-4 , Unicel: 4CH-35 , Filbur: FC-0161, Diameter: 4-5/8", Length: 16"

Filter Specifications:

• Square Footage: 35 sq. ft.
• Media/Thickness: 4
• Diameter: 4-5/8"
• Length: 16"
• Top: Handle
• Bottom: 1-1/2" MPT

Equivalent to:

• Pleatco: PTL35P4-4
• Unicel: 4CH-35
• Filbur: FC-0161
• OEM: 6540-486
• Darlly: 40351

This Filter Fits The Following Brands:

Hot Springs, Watkins, Tiger River, Sundance Spas

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