small digital tube indicator voltmeter round panel digital voltage meter indicator electronic measurement type: AD101-22VM place of origin : Zhejiang Province,China(Mainland) brand name : NIN mounting diameter: 22mm color : white green red yellow blue display type : digital display voltage measuring range : AC50V-500V frequency compatibility range : 50-60HZ display resolution : 1V sample rate : about 1 time/s no input signal hint message : display 000.