VDO Direct Mounting Gauges are only 1 1/2" in diameter and can be used right on the engine to monitor fuel or oil pressure. Use the Direct Mount Gauge "under the hood" while you dial in all types of fuel management systems from carburetors to fuel injection. Direct Mount Gauges are designed to withstand engine vibrations and are packaged in select housings. Direct Mount Miniature Gauges are equipped with a 1/8" pipe filling and can be screwed directly into pressure lines, fuel rails or the engine oil galley. Choose from two pressure settings in black with red dial or white face and black dial.