Hi, I used one with DD. It was my dads, I have been using them since I was little for sports injuries. It was one that was constantly on and you did not have to press any buttons for it to work. I loved it and was even playing UNO with DH while I had it on. But eventually I could not even feel it over my contractions. But it did help me through the beginning so I will probably give it another go this time around.