I bought for my wife, she is very good runner, but suffers from iliotibial band syndroma nd back pain last 3 months. She tried physio, stops running for a while. She has Trion Z for 2 weeks, getting better, back to running. But I am still sceptic :) and therefore I am going to buy this product as well, I am runner and golf player, having back pain, bad days/ good days. I will give you my experience later. Otherwise very good service, one day delivery, size OK.