As the name says... rapid relief!!!!
Nice size for knee or back pain,  Quick to freeze.  Slower than most to lose its cool.  Don't use heat for my pain so I don't know how well they would retain heat.  Would definitely buy again.  I've had one half this size for years and it was STILL my go to before buying this.  (Do wish they still came in that half size though).  GREAT product!!!
Rating: 5 stars