Integrated Anti-Slip System - Maximum safety with the integrated anti-slip system. A set screw molded into the sliding arm interlocks with the serration on the rail. Reinforced Jaw and Sliding Arm - Corrugated malleable cast iron fixed jaw and sliding arm generate powerful, rigid clamping. High Quality Profiled Rail - The profiled rail has been optimized for clamps. The profile acts against torsional forces. Smooth Running Spindle - Smooth running spindle with Acme thread allows for more clamping with less effort. Replaceable pressure plates. Comfort Handle - The series offers the tried -and -true wooden handle . Patented profile rail Non-slip locking device 1 beam design Zinc finished drawn rail Non marring pads