All Brass Replacement In Tank Check Valve for Ingersoll Rand 54368154. 3/4" Inverted Flare Top Inlet x 3/4 MNPT Outlet With 1/4" FNPT and 1/4" Inverted Flare Unloader Ports. Air inlet threads: 3/4" Inverted Flare Which Measures 1 1/16" in Linear Inches. Outlet threads: 3/4” male NPT which measure about 1 1/32” in Linear Inches. Side Unloader Port: 1/4” Female NPT Threads Which Measures .540” in Linear Inches, 1/4" Inverted Flare Which Measures 7/16" In Linear Inches. This style is used to directly screw into the air tank and keep pressure from leaving the tank and putting pressure against the compressor pump once the compressor is shut off.