150PSI Modular Bulkhead Fitting. Base Bulkhead Fitting All the Modular Bulkhead fittings start with one of the four base bulkheads. This one is for a 1" hole, up to .0625 (1/16)" wall thickness. It provides 3/4" through path. The 3/4 side has an o-ring for sealing, no gasket needed. You can also use any fitting with 3/4" FPT, such as a female adapter, swivel adapter, threaded Tee, etc. in place of using the provided nut. The other side has a 1" straight thread male.
Also used to convert FPT (female NPT) fittings to MPT modular systems via a 90° elbow. Aka a national pipe thread gender changer. Designed for going into METAL (brass, steel, iron, etc.) threaded fittings. Made in the U.S.A.