Caution! Would have given 5 stars as I have purchased this item two other times but this last one I bought started getting these huge air bubbles like big boils or blisters throughout the mat and it seemed like it happened about a week or so after I got it? I live at altitude so maybe there was a problem with production and to much air was unevenly inserted into the mix and the air bubbles are expanding like when traveling and your shampoo explodes? It is a mystery and the big bubbles ( the size of a saucer) cause the mat to be uneven so very bad for balance especially for a "mat" So I guess purchase at your own risk because I just decided to inspect the other mats and they also have seemed to develop this disease. I wonder if anyone else has had this issue?