Features and Benefits * The 550 is used to check for voltage leaks on the Hybrid car electrical wiring * The 550 can supply 250V, 500V and 1000V test voltages for doing complete insulation testing * CAT III 1000 volt safety rated Digital Multimeter * Large dual display with white LED backlighting * Includes (6) AA batteries, test leads and blow mold storage case You can not easily test for high voltage leaks to ground without a high volt test source. The 550 can supply 250, 500 and 1000 Volts into a circuit that is leaking to ground. The following parts can leak high voltage to ground: Battery Pack, Power inverter, DC-DC converter, High Voltage AC compressor, Power steering pump. In addition, the 550 can supply 1mA of test current for the capacitance load. It is auto-ranging and can measure up to 2000 MegaOhm with a resolution of 1 K Ohm. Other features include: double injection mold housing, hands free operation via "power lock-on" feature, 200mA small current for continuity test, over range indication and low battery indication. Always use approved safety gloves while testing electrical circuits on Hybrids.