Features: 1.Headphone function: In a noisy environment, you can wear headphones for operation to avoid external interference. 2.Light function: In the dark or dark environment, you can flip the light switch up to turn on the light, which is convenient for you to work as usual 3.Volume adjustable function: When hunting, you can turn the volume adjustment knob on the receiver until the sound level is appropriate 4.Energy saving: Light touch switch, automatic delay shutdown, battery continuous working life is more than 50 hours. 5.Application scope: telecommunication network line engineering and routine maintenance work; computer network line engineering; other metal wire line engineering and maintenance work Notice: Please allow 1-3cm deviation due to manual measurement Actual color may be slightly different from the image due to different monitor and light effect Description: Signal output level: 8Vp-p Signal transmission distance: 3km Size: Transmitter: 126X49X34mm Receiver: 175X42x27mm Battery:Built-in battery Package List: 1 set x Wire Locator