The MICRO 100 QC-3 Hex screw for locking in the tool in the bottom position of the QDL and QDLM style dog leg Micro-Quik toolholders. Requires a QHK-1 hex key The Micro-Quik Tooling System provides maximum centerline repeatability within plus or minus 0.0005" from tool to tool. When all of this systems components are used together, this unique system reduces machine setup, downtime, tooling costs, and tooling inventories all while boosting productivity. For over 45 years, MICRO 100 is a known industry leader and internationally acclaimed when it comes to solid carbide tooling.