The MILWAUKEE® SDS PLUS 4-Cutter MX4™ 5/16" X 4" X 6" Drill Bit 15 Pack with solid head carbide deliver up to 5X longer life in concrete with rebar. Engineered with rebar guards to provide maximum durability in hard aggregate and rebar with a 4-cutter design that prevents lock-up, reducing downtime. The sharp centering tip offers exact spot drilling in concrete and metal decking. Variable flutes remove dust faster, reducing heat and delivering up to 20% more holes per battery charge. A wear mark indicator shows end of life and when bit no longer meets the ANSI requirement. The Milwaukee MX4™ 4-Cutter Drill Bits are ideal for concrete with rebar and masonry applications.