Bosch’s hole saw product line, features the HDGQA Mandrel with an AutoStart centering pin. The carbide-tipped centering pin centers the hole saw precisely and then it retracts to allow the hole saw teeth to engage the material, eliminating the need to pre-drill a pilot hole. With the AutoStart and Bosch's Diamond Hole Saws (sold separately), cutting holes in porcelain, ceramic, glass, limestone, granite, travertine, slate, or marble has never been faster or easier.