Pentair Manifold Internals 400K BTU | 77707-0209 Quote They have several steel balls

They have several steel balls that are water lubricated (do not lubricate with grease) located inside which give the ability for easy movement

✔ Test After Replacement: After replacing the fuse

They also have grooves on the backside where the springs are to be installed that helps the movement of the flaps

5” vacuum hoses for optimized suction and cleaning

Upgraded spring and locking tab ensure reliable pop-up

Pentair Manifold Internals 400K BTU | 77707-0209 Quote They have several steel ballsPentair Manifold Internals 400K BTU 77707 0209 The Pentair 77707 0209 Manifold Internals kit is a complete internal replacement set for 400,000 BTU Pentair MasterTemp and Sta Rite Max E Therm pool heaters. This OEM kit includes essential components that help restore proper water flow and heat distribution within the heaters manifold system. Features: Internal component kit for 400K BTU models Includes bypass valve, spring, and internal manifold