Wrench hex is .562" on the -4 nut and .875" hex which is drilled and tapped 1/8" female pipe on two sides allowing the racer options where to stick there Co 2 pressure gauge.
Picture four, five and six are shown to give the racer an idea on how to plumb and connect all the parts when using a 150/250 all in one regulator but each piece is sold separate.
Fitting includes a internal hex plated steel 1/8" pipe plug to plug off the side of the fitting the racer doesn't use.