The Ryobi Countersink Set AR2008G includes 4 black metal drill bits in sizes #6, #8, #10, and #12, suitable for use with air drills, drills, and rotary tools. The set is designed for applications such as cutting and grinding, with a 4-inch diameter and 3-inch depth for versatility. This unit is suitable for drill or impact use, making it a versatile and reliable addition to your tool collection.