For Ingersoll Rand Replacement 1/2" Female NPT x 3/4" Brass Air Compressor Check Valve 97162812Aftermarket Check Valve for Ingersol Rand Air Compressor 1 2" Female NPT x 3 4" Male NPT One new Aftermarket 1 2" female NPT x 3 4" male NPT in tank air compressor check valve, part number: 97162812 for Ingersoll Rand. This style of check valve is usually screwed directly into the air tank, then the main line coming off the compressor is connected to it. This valve prevents backflow or tank pressure from getting back to the air compressor pump once