Holders ending in QC have a quick-change mechanism that requires no tools to change the hole saw. 3834-ARBR-9100, -11152 and -16152 feature Power Driver™, which increases strength and reduces backlash by redistributing load from the threads to the solid cover. Holders can be used with carbide hole saws, but we recommend using the carbide center drill. point, 3834-DRL-CT, for cutting abrasive materials Holders can be used for multi-construction hole saws, but drill 3834-DRL-L must be used HSS pilot drill is included with all holders, for use in metal and wood applications Easy hole saw change with quick change mechanism Spare screws available