Bosch Bulldog Tough 4 Cutter 18 in Alloy Steel Masonry Drill Bit for SDS Plus Drill Flooring Nailers Enhanced Mobility: Features 7 inch all terrain 1000088971 Enhanced Mobility: Features 7 inch all terrain wheels and an extendable metal tubular handle Its soft closing doors also ensures safety for the entire family Durable SDS plus® bit design – features a four cutter head with four flute technology for 2X life in concrete with rebar and hard aggregate Four cutter head design – ensures that one angle is always hitting rebar to help prevent the bit getting stuck Four flute bit technology – aggressively pulls dust away from hole