My friend had picked up 10 amps. He tried them and said that he could not sleep and his leg hurt so much he was unable to walk for like 6 hours. He only managed to do 5 of the 10 amps he bought so he GAVE the other 5 to me for free. SO of course I had to try them and they hurt so bad I couldn't believe it. I was unable to work out because I could not sit on any of the machines. I personally had a bad experience wit them and so did a good friend of mine. I believe they were over priced as well. I would not recommend taking them. It could seriously mess up your workout routine.