New 10pc Countersink Drill and Drive system is easy to use and will save time and frustration. Start by inserting the Quick Change magnetic hex drive shaft into your drill. Then choose from #6, #8, 10, or #12 countersink that corresponds with the screw that you are using and insert it into the quick change shaft. Drill your pilot hole all the way down for countersinking or for no countersink stop drilling before it gets to the boreing cone. Once your hole(s) are drilled push and twist the knurled part of the quick change shaft forward to release the drill bit and flip it to the other side which will be preloaded with your correct screw driver bit in order to drive the screw(s) in. No more fumbling in your pockets or behind your ears for bits. Driver bits has a powerful magnet so your screws won't get away from you. Comes with 5 Phillips bits in assorted sizes, but they are replaceable so they can hold torx or square head bits as well. Drill Bits are replaceable as well, just use the back of the quick change shaft which has an allen head set screw built in to loosen the drill bits. Also bit lengths are adjustable so you can make the bit depth longer or shorter to your desired pilot hole depth. Product features: 4X faster and easier drilling and driving Drill, countersink, counterbore and screwdriver functions Patented on-board hex key for convenient, fast tool changes Magnetic driver bit tip provides a strong fastener retention Works with all electric and battery powered drill/driver brands Manufactured utilizing high quality materials for durability and long tool life Made in the USA Set includes: 4-in-1 Drill & Driver with modular insert (5) assorted 1 in. screwdriver bits (4) countersinks: #6 with 3/32 drill bit, #8 with 7/64, #10 with 1/8", & #12 with 1/8"