After years of research and testing, Park Tool's built what they consider the best shop clamp made. It's smooth, versatile and built to stand up to everyday shop use. - #100-3D fits the following repair stands: PRS-2, PRS-2 OS, PRS-2 OS-1, PRS-2 OS-2, PRS-3, PRS-3 OS, PRS-3 OS-1, PRS-3 OS-2, PRS-3.2-1, PRS-3.2-2, PRS-4, PRS-4 OS, PRS-4 OS-1, PRS-4OS-2, PRS-4W and PRS-33 - #100-5D fits PCS-4, PRS-7, some models of PRS-5 (with composite top tubes), and PCS-1 models manufacturer post 2002. (Note: Inspect top tube below lever for an embossed "939") - #100-25D fits PRS-25, PCS-10, PCS-11, PCS-12 (and PRS-15 with 1951-15 Adaptor Stud) - Grips nearly any tube from 7/8" to 3" (23-76mm), including aero tubes - Micro-adjustability allows perfect clamping pressure every time and prevents damage to thin-walled tubes - Long travel cam handle allows quick entry, adjustment and exit - Versatile: It grips nearly any tube including aero shaped tubing and seat posts 7/8" to 3" (23mm-76mm). Its narrow clamping jaws (2.7"/7cm) are designed to clamp securely yet fit into tight areas or on short seat posts. - Durable, replaceable jaw covers - Soft Touch saddle cradle provides a perfect spot to temporarily rest a bike by its saddle - Built to last: Powder coated, precision machined, die-cast aluminum main body parts and high quality small parts - Fast operation: Cam-actuated adjustment system for quick entry, adjustment and exit, plus handy "spinner" handle helps speed large size range adjustments