OK Belay Biner
Bought this to try out with my belay device, does ok, although it does spin around a lot
Pros: Smooth stock results in not a lot of friction, which makes this carabiner nice for fatter ropes. Keylock is easy to unclip from anchors or ropes. Burly 10kN strength when crossloaded. Cheap
Cons: Triangular shape makes this guy shift and flip a lot when belaying. Spine is not round like the rest of the carabiner. Likes to rest on the flat spine when used with an autoblocking device off of the anchor. I've seen smoother screwlocks.
Not bad, but you should probably just get a Petzl Attache.
Hope that was a help