The strength and durability of heat-treated screw and nutdriver bits make them a great choice for the demanding professional, and that dependability is exactly what you get in the DeWalt DW2161 21-piece set. The advanced hardening process used in the creation of these tools allows them to provide higher torque and improved driving power, so you get jobs done faster and more efficiently. And they come neatly packaged in a heavy-duty case made from industrial-grade ABS material, so you never end up sorting through the bottom of a big tool kit for a little bit tip. This durable case also offers an interlocking hinge and a sliding, rubber lock, so you can count on it to stay closed and hold up to the test of time. Labeled slots for each bit and an advanced bit holder help you stay organized and ensure that you know which bits are which at a glance. Included in this kit are a no. 1, no. 3, and six no. 2 1-inch Phillips insert bits, no. six, no. eight, and no. 10, slotted 1-inch bits, a no. 1, no. 3, and three no. 2 square recess bits, a no. 3 Phillips two-inch power bit, a no. 2 square recess two-inch power bit, a quick-change magnetic bit holder, a 1/4-inch nutdriver, and a 5/16-inch nutdriver.