Park Tool Professional Micro-Adjust Repair Stand Clamp (PRS-2, PRS-3, PRS-4, PRS-2 OS, PRS-3 OS, PRS-4 OS, and PRS-4W) Fits all generations of our PRS-2, PRS-3 and PRS-4 stands One handed tightening Quick release button allow head to pivots 90 degrees to clamp either top and bottom or left and right sides of tube Adjustable clamping pressure prevents damage to even thin walled tubing Narrow 3.5 inch (90mm) jaws for clamping in tight access areas