Combination of oil pressure, volt and water temperature with 2-1/16 (52,4mm). Range of the oil pressure is 0-100 PSI, volt is 10-16 and water temperature is 130-280 degree F. Includes 6 feet nylon tubing with 1/8" NPT fittings and 1/4'', 3/8 and 1/2'' NPT adapter fittings. No electrical power for operation. Ideal choice for vehicles with no or low powered electrical systems