Amazon カスタマー 5 pays off but problem doesn't last long! I have braces and the only thing I have to live with is buying gel sticks! doesn't last long for me! I have severe pain I use it every day for more than 6 hours! sometimes I take shocks cause very thin gel ok! happens I turn on the device seems to feel stronger shock I believe should make gel a little thicker would improve quality product for sale!