This product is a battery powered digital insulation resistance tester. It is equipped with a micro processor chip and has high precision, stability and reliability. Features: COMP Function: In the insulation resistance measurement mode, press the "COMP" key to open the compare function. This insulation resistance can be selected as 100K, 200K, 300K, 400K, 500K, 1M, 2M, 3M, 4M, 5M, 10M, 20M, 30M, 40M, 50M, 100M, 200M, 300M, 400M, 500M comparison value, and press and hold this key to exit the compare function. Press the key in the low resistance position to open/close the continuity beeping function. ZERO Function: In the continuity/low resistance measurement mode, press the "ZERO" key to turn on/off the Zeroing function, which is only effective when the short-circuit resistance is less than 2. HOLD Function: In the non-insulation test mode, press the "HOLD" key to enter/exit the reading holding mode. In the insulation resistance test mode, when a single measurement ends, the HOLD mode will be automatically activated. Press the key to exit HOLD mode. LOCK Function: This function is only valid in insulation resistance measurement mode. Press this key to turn on/off the LOCK function. In the process of insulation resistance measurement, press the key to end the measurement. Polarization Index(PI)/Dielectric Absorption Ratio(DAR): In the insulation resistance test mode, press this key when the measurement is not started to turn on/off the polarization index/dielectric absorption ratio measurement function. When this function is on, PI(10min: 1min) and DAR(60s: 15s or 60s: 30s) can be selected. After the PI/DAR measurement, press this key to switch the ratio of insulation resistance value. TEST Function: In the insulation test mode, when the LOCK function is on, press the "TEST" key to start/end the test. When the LOCK function is not on, press and hold the "TEST" key and keep measuring, and release the key to end the measurement. Backlight Function: In the ON state, press this key to turn on/off the LCD backlight. If the backlight is not turned off manually, it will turn off automatically after 30 seconds. Specifications: Material: ABS AC Voltage Measurement: 1.0~600.0V (50/60Hz), 0.1V, ±(1.5%+5) DC Voltage Measurement: 0~±600.0V, 0.1V, ±(1.5%+5) Frequency Measurement: 1~1KHz (voltage≥10V), 0.1Hz, ±(0.5%+3) Low Resistance Measurement: 0.00~200, 0.01, ±(2%+5) Insulation Resistance Measurement: 50V (100%~120%): 0.00~50.0M, 0.01M, ±(1.5%+5) 50~500M, 1M, ±(5%+5) 500M~1.0G, 1M, ±(10%+5) 100V (100%~120%): 0.00~100.0M, 0.01M, ±(1.5%+5) 100~500M, 1M, ±(5%+5) 500M~5.0G, 0.1G, ±(10%+5) 250V (100%~120%): 0.00~200M, 0.01M, ±(1.5%+5) 200~1000M, 1M, ±(5%+5) 1.0~5.0G, 0.1G, ±(10%+5) 500V (100%~120%): 0.00~500M, 0.01M, ±(1.5%+5) 500~1000M, 1M, ±(5%+5) 1.0~10G, 0.1G, ±(10%+5) 1000V(100%~120%): 0.00~2000M, 0.01M, ±(1.5%+5) 2.0~10G, 0.1G, ±(5%+5) 10~20G, 1G, ±(10%+5) 20~100G, 1G, ±20% Battery: 4 * AA alkaline batteries (IEC LR6) Altitude: Operating Altitude: ≤2000m Storage Altitude: ≤12000m Storage Conditions: Temperature: -20~60/Humidity: 75%RH or less (non-condensing) Operating Conditions: Temperature: 0~40/Humidity: 85%RH or less (non-condensing) Temperature Coeffcient: When the temperature 18 or 28, the coefficient=0.1x(specified accuracy)/ Item Size: 190 * 100 * 55mm / 7.48 * 3.94 * 2.16in Item Weight: 458g / 1.01lb Package Weight: 815g / 1.79lb Package Size: 23.5 * 15 * 7cm / 9.25 * 5.91 * 2.76in Package List: 1 * Insulation Resistance Tester 2 * Test Leads 2 * Alligator Clips 4 * AA Alkaline Batteries 1 * Storage Bag 1 * User Manual (English)