PanaVise Products,Inc. designs, develops and manufactures some of the most innovative, well built work holding fixtures available. We believe offering their unique Component System of interchangeable heads, bases, and base mounts will allow you to create a custom made holding tool for your specific needs. All PanaVise Bases include the patented Spilt Ball which allows the head to be positioned through three planes ( 90 degree tilt, 360 degree turn and 360 degree rotation). All 300 series Bases accept all 300 series Heads. They are used extensively in the electronics, lapidary, watch repair, hobby world, and are a must for product development labs. PAN-311 Bench Clamp Base Mount Clamp to bench, table, ladder, or tool box. Clamps to anything up to 3-7/16 thick. Throat depth 2-5/16. Drilled and tapped with three (3) 1/4-20 holes evenly spaced on a 4-5/16 bolt circle. Includes four (4) non-marring, anti-skid neoprene pads to avoid excessive tightening.