Mooneyes oil pressure gauges measure 1-1/2" diameter, measure from 0-60lbs., liquid filled, and offer an accurate oil pressure reading on your Harley-Davidson or other motorcycle. They are 1/8 inch NPT thread, and can be used with a variety of oil pressure gauge adapters and fittings available in both chrome or brass. Check out the Oil Pressure Gauges and Mounts category for gauges and fittings to go along with this adapter.