Bosch Drill Bit HCD2051 SDS Plus Speed Clean 5 16 x 9 Inch Hollow Concrete Masonry (Hollow Extraction Core 4.25 In Usable Adhesive Anchor Boring) Impact Drivers Professional Aluminum NPSH Hose Shank Professional Aluminum NPSH Hose Shank Coupling with Heavy Duty Brass Nut The high contrast color ink filled stamped size markings increase tool visibility by 50 percent to accelerate workflow efficiency and reduce eye strain in grease covered automotive shop environments this hollow extraction bit connects to jobsite extractors using the included rubber adapter Solid Carbide Two Cutter Head: Thermally brazed carbide cutting tip maintains hole diameter accuracy and provides service life comparable to solid drill bits