Horn gets caught on biner
This device is nearly perfect except for one fatal flaw. It works smoothly for a wide range of rope diameters, the locking mechanism works well off the harness and off the anchors, it's lightweight, it's durable, it's simple, and it's inexpensive. It seems to solve the problems of all it's predecessors. However, I no longer use it because of one fatal flaw. The horn has a tendency to get caught in the carabiner causing the belay to lock-up, which is a real nuisance and potentially hazardous. Even with a wide HMS carabiner this happens often.