The device is very easy to use (provided you forget the reflex remote control as the "enter" key is on the left side and not in the center) light, very effective depending tens and massage; for muscle function, it is more difficult to assess the results. I had doubts about the batteries, but after three months of daily use at a rate of 30 to 40 minutes a day, I still have not had to change the original batteries! It will buy the electrodes, but it is the case for all these devices. One downside, but linked to the site, not the product itself: the use of such devices is prohibited for people with certain medical conditions, such prohibitions should be clearly indicated before purchasing. It might also wish that the brand produces a four-channel device.