It worked the first time
The first time I used this I soaked it for almost 20 minutes.  I heated it for 60 seconds, then 30 seconds increments and it worked ok.  The second time I tried to use doing the same thing, it didn't work.  It burst and the gel started leaking, it has become flat. I am a week and a half outside of my window of being able to return for a refund.  Now it's just money lost.
Rating: 2 stars