Milwaukee SDS-MAX MX4 1/2"X15" X 21" rotary hammer drill bits are engineered to deliver exceptional performance and durability. Featuring the innovative MX4 4-Cutter design with solid head carbide, these bits provide up to five times longer life when drilling through concrete with rebar. Designed with sharp centering tips, they ensure precise spot drilling every time. The integrated 4-cutter design prevents lock-up in rebar, significantly reducing downtime on the job. Optimized flutes efficiently remove dust, reduce heat buildup, and allow you to drill up to 15% more holes per battery charge. Each bit includes a wear mark indicator to help you know when it no longer meets ANSI requirements. These drill bits are i for tough concrete with rebar and masonry applications, making them a reliable choice for professionals seeking durability and efficiency. Model Number: 48-20-3904