Amprobe RS-3 PRO CAT IV 300A Analog Clamp Meter Analog multimeter has a broader operating temperature range than digital multimeters and can be used outdoors Analog clamp meter measures alternating current (AC) to 600 amp, RMS AC voltage to 600 volts (V), and resistance to 1,000 ohms Transformer clamp with 1.64" (41 mm) jaw opening measures current without interrupting or touching the circuit Needle lock secures the needle in place to protect it from damage during transport and holds the needle at a reading, even after the meter is disconnected Meets International Electrotechnical Commission (IEC) safety standard 61010 and is certified for category IV installations up to 600V Measures AC current up to 300A Voltage up to 600V AC Works in temperatures from 5-DegreeF to 122-Degree F Operates on 50 and 60 Hz frequency Easy to use rotary scale