The small vise has a plastic, non-marring, insert in the jaw. Its good for holding small pieces for detail work like filing or polishing. Its heavy enough that you don't have to mount it to a benchtop although sometimes a c-clamp will help steady it if you are being agressive. The large vise is heavy enough for any kind of work. I've found that a square of leather wrapped around the workpiece, rough side toward the workpiece, allows you to clamp a pistol frame tightly and do some fairly heavy work without it shifting or marring.