Indicator Frequency meter 0-99Hz led digital display electricity frequency meter frequency counter type: AD101-22HzS place of origin : Zhejiang Province,China(Mainland) brand name : NIN mounting diameter: 22mm color: white green red yellow blue display type : digital display supply voltage : AC 50-380V frequency measuring range : 0-99HZ display resolution : 1HZ sample rate : about 1 time/s no input signal hint message : display 000