New series AC 20-500V waterproof mini led indicator voltmeter digital display voltage meter digital Indicator AD101-22AMS type: AD101-22VMS 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 : AC 50-500V frequency measuring range : 50-60HZ display resolution : 1 V sample rate : about 1 time/s