ZJchao Digital Ac 300v 50a Blue Lcd Dual Panel Volt Amp Combo Meter Digital AC 300V 50A Blue Lcd Dual Panel Volt Amp Combo Meter +CT Need No Power Having a dual measurement of AC voltage, AC current with AC current transformer It can measure AC 110V 220V 240V; Display Range (max) : 300V/50A (Please don't exceed the 300V/50A) It needes no extra working Power,the wires of CT can be extended as you want It can be easily and Widely installed in the complex environment.