Feature: Dual-Channel TENS&EMS Device Adopt TENS and EMS low-frequency pulse techniques to relieve pains or relax tight spots. And with dual-channel output, it allows use by 2 person or in different areas. Considerate Design It offers 12 massage modes with each one owning 40 strength levels, free to choose to fulfil your different needs. LCD Display You can easily get to know the current massage mode, strength level and preset time of 2 channel. Adjustable Timer You can adjust time from 5 to 90 minutes by press "Timer" button, and long press to be mute or produce buzzing sound. Pocket Size It owns compact and stylish design and comes with belt clip, easy to take it with you anywhere. Specification: Material: ABS Channel quantity: 2 Power supply: DC 4.5V 3 * AAA battery (Not included) Waveform: Bidirectional wave Display mode: LCD display Mode: 12 modes Strength levels: 0-40 Output frequency: 1~120Hz Output pulse width: 100~250uS Output voltage: 40V20% Operating temperature: 5~40 (41~104) Operating humidity: 15%RH to 93%RH Storage temperature: -25~70 (-13~158) Storage humidity: 15%RH to 93%RH Item size: 137* 67* 20mm/ 5.39* 2.64* 0.79in Item weight: 74.4g/ 2.62oz (Only the host) Packing list: 1 * TENS & EMS Device 4 * Electrode Pads 2 * Electrode Cables 1 * User manual