Features Specifications:Sell TENS Unit EMS Unit HT-339 4CH  Features Four EMS programs with medium frequency 1000~5000 Hz carrier  Alternate rate of output for massager are auto & manual changedSpecification Dimension : 200mmx 145mmx 72/38mmPower supply : 1.5Vx 6 battery or DC 9V adaptorChannels : 4 independent isolated transformerOutput current : 120mA peak-peak of 500Ω loadTimer : 0~60 minutes select & continuousWave form : 1000Hz~5000Hz frequency carrier Mode : Four mode P1, P2, P3, P4 can be selected MA : auto program/rate & density auto changeMT : two sets of two channel auto alternate outputMM : 4 channels alternate output/rate adjustableC : carrier frequency & modulation rate adjustable Accessories 4 Channel stimulator-------1Electrodes lead Wire-------4Electrodes pads--------------8Instruction manual----------11.5V Battery--------------------6AC/DC adaptor----------------1Leather case------------------1