The DWA19SD77 77-Piece set offers a variety of professional grade screw driving bits. The set also includes nut setters and a compact drive guide. DEWALT screw driving bit tips are a perfect complement to your drill/driver, and are designed to meet the demands of working professional contractors. Each bit is cut from shock-resistant tool steel and features an advanced hardening process that greatly reduces wear. Its snub-nose design fits perfectly into hex-socket adapters and the tips are precision ground to seat firmly into the screw head.