I belayed on this for years with no problem. Until there was one. He was about 75 pounds heavier than me, and while he wasn't falling, he wasn't stopped either. Without teeth I was only able to perform a slow, controlled descent (~2ft/min). Safe, but no longer good enough for my needs. It works, but I don't recommend teeth-less ATCs to friends anymore. I still keep mine as a spare. Better than no device!