This is a 1/4" mnpt twist style moisture tank drain. Also known as a petcock. This is o-ring sealed for easy use, features a knurled twist grip and is made of solid brass. (Note: 1/4" pipe threads measure about 1/2" in diameter if using a tape measure.) These are commonly used on air compressor tanks and are rated up to 200 psi working pressure.

Specifications:

Rated up to 200 psi Working Pressure
Material: Solid Brass
Easy Open / Close
Easily attached using a 9/16" wrench.

1/4" Male MNPT Threads (measures about 1/2" diameter when using a tape measure)