Four-cutter carbide tipped head design – delivers up to 2X life in concrete with rebar (vs Hawera SDS-plus two-cutter concrete drill bit) Four-cutter head – provides four cutting edges to hit rebar, to help prevent the bit from getting stuck Centering tip – ideal for drilling anchoring holes to enhace the precision of hole placement Four-flute design – standard flute design efficiently pulls dust away from the hole Sizes included (Diameter/Usable Length/Overall Length): 3/16" x 4" x 6", 1/4" x 2" x 4", 1/4" x 4" x 6", 3/8" x 4" x 6", 1/2" x 4" x 6" Bosch-made carbide – manufactured by Bosch with quality materials promoting durability and longer life.