The 6" shackle (vs the 9" shackle which is fine) is not properly designed or manufactured. The first issue is that the mechanism doesn't lock (regardless of how the screw is set), which is ironic given that it's a locking pliers type of thing, useless as a drill clamp. Additionally, since there is very little clearance between the bottom handle and the deck of the drill, it's impossible to wrap your fingers around it to squeeze the handles. I wonder if they ever tested these things before release? This review is for the 6-inch only, while the 9-inch is completely different and very good. I've been using the 9 inch every day for several months; I only wish they made the same clamp with a shorter reach (i.e. 6 inches).