THIS ECONOMY TESTER IS USED ON FUEL INJECTION SYSTEMS WHERE TESTER CAN TEE INTO THE LINE BASIC FUEL INJECTION TESTER INCLUDES LARGE AND SMALL SCHRADER ADAPTERS& M6-1.00 O-RING ADAPTER, AND TEE MANIFOLDTHE 63MM GAUGE HAS A DUAL SCALE DIAL WITH RANGES FROM 0-100 PSI AND 0-7 BARNOTE: WILL NOT FIT BOSCH-CIS-JETRONIC & GM THROTTLE SYSTEMS