Vacuumate™ with BatteryCaracteristicas: Industry standard for fast and accurate synchronizing for up to four carburetor fuel injection throttle valves Can be used with two or four stroke engines Four LED bars display manifold pressure, even in sunlight Built in tachometer displays engine idle speed up to 2000 rpm Dynamic mode to troubleshoot poor engine synchronizing Includes a rechargeable 7. 2V NiMH battery (can also be powered and recharged by the internal battery)