The 311 from PANAVISE is a Bench Clamp Base Mount that is compatible with the 201 PV Jr. Vise and 300 & 305 Bases. The 311 includes four non-marring, anti-skid pads for additional anti-slip characteristics without excessive tightening of the clamping screw. Finger grip for added convenience. Take your vise anywhere you need it! Clamps to anything up to 3.4375" (87.3mm) thick.