Really frustrated with this thing - simply does not function has a sprocket holder. The pegs that fit into the sprocket spaces slip out very easy. The adjustment screw keeps the arms from closing any further rather than opening - what?! Obviously the physical presence of the sprocket is going to keep the thing from closing, what I need is a stopper screw to keep it from *opening.* I don't believe the builders of this product ever actually tried to use it - if so, and they're selling it anyway, they are absolute crooks. Tighten the hinge as tightly as your want (with a screwdriver, at that), it will slip open/off under any type of twisting pressure from the sprocket. Simply put, this sprocket holder does not hold sprockets. Do not buy!