"• Analog clamps measure volts and amps - no batteries required • Measures AC Current up to 300A (1000 A model RS-1007)• Voltage up to 600 VAC• Resistance and continuity• Pointer lock with data hold• Easy to use Rotary Scale• Measures Volts and Amps, no batteries required• Works in temperatures from 5°F to 122°F• Operates on 50 and 60 Hz frequency These CAT IV 600V safety rated analog clamps are great tools for tough electrical applications. Clamps work well in extreme temperatures of 5F to 122F, while digital clamp LCD screens tend to freeze, this anolog clamp measures up to the test."