Hot Tub Spa Pump Union Coupling Fittings 3" Threaded for 2" pvc pipe size, PAIR of unions, exactly as shown and described. Inside diameter of the threads is 3.005" (minor thread diameter). CONFIRMED.

The female slip socket is pvc material, glues to your 2" ASTM Schedule 40 pvc pipe or fittings, female socket size is industry standard 2-3/8" inside diameter, CONFIRMED.

This female socket diameter is tapered, per ASTM standards in order to glue onto male fittings or 2 inch pvc pipe. CONFIRMED.

Fits normal spa pumps with 3.065" outside diameter threads (major thread diameter), Waterway, Ultra Jet, Aqua-Flo, etc. which have normal, spa industry standard buttress threads measuring approximately 3.065" in outside diameter. This special spa industry buttress thread has 8 threads per inch, and is NOT commonly used on pool pumps, but on hot tub pumps only. The inside diameter of the female threads is 3.005", and the outside diameter of the nut is 3.4"

THESE WILL NOT FIT POOL HEATERS, WILL NOT FIT POOL PUMPS, not for Hayward pumps, not for special Jacuzzi swivel union threads, not for some chinese pumps, NOR OTHER DEVICES. They fit American made hot tub pumps only, and only those that have 3.065" outside diameter threads.

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