We bought two of these for indoor rock climbing and love them. We double and triple checked to ensure they were safe, and even asked the people at the front desk, who couldn't find any concerns with them. That being said, we used these in a safe, indoor area with padding underneath us, and we're both relatively in good shape. As far as using them outside, differing body types, etc. I can't speak to its usefulness, but for indoor rock climbing it's great.