Carvin 1-1/2" FBT x 1-1/2" S Black Pump Union [Qty 2] (31175608R2-BLK) filters Check valves are useful because

Check valves are useful because they help prevent undesirable reverse flow that can interfere with normal system performance

Improves repair precision and operating confidence

and this Jacuzzi Whirlpool Bath HTA version comes in white and is supplied without the nut and backup ring using the 4870940 reference

installation can be cleaner than trying to piece together separate components

Genuine or listed Pentair/Sta-Rite replacement option for Fittings & Valves: Dial Valves applications

Carvin 1-1/2" FBT x 1-1/2" S Black Pump Union [Qty 2] (31175608R2-BLK) filters Check valves are useful becauseThe Carvin pump union set is designed for compatible 1 1 2 inch plumbing applications where a serviceable connection is needed at the pump. A union like this is useful because it helps create a removable plumbing joint, making future maintenance or equipment removal easier without sacrificing a secure installed fit. This black two piece set is especially useful when the original unions are cracked, leaking, worn, or no longer threading together