You can't use 2 of these on 2 vices less than 8" apart if you're like me and want them to stay there permanently. I want to shorten the handles so I have one on each vise, side to side only 6 inches apart. Also, I plan to sink the front center so the socket or original handle can still be used on the outside without removing that handle. Don't hit your knuckles. I like it!