Whoever invented and thought these would be good to lock a scope in place via the dovetail bar has serious issues. These absolutely suck!!! Damaged my new mount's scew and can easily break or rather twist around if slightly overtightened. Useful on the legs of the tripod but even there it's just dumb because they touch the floor when you screw or unscrew having to lift the mount to make it spin around. Seriously annoyed by iOptron's rational on quite a few things...........