This is a great training tool. However, at almost $100 each, they bend way too easily. Bending occurs when swimmers are asked to return the mirrors to be stored and as they attempt to lift them off the bottom of the pool, suction holds the mirror down and the metal quickly bends. When this occurs, severe image distortion results. Of the 4 mirrors I bought for my team, 2 were bent within the first day. I understand that with more patience the mirrors can be lifted without bending, but as an experienced swim coach, I know that this type of patience from swimmers (especially young ones) is hard to come by. Again, great training tool, but not worth the money.