This has to be the best tool ever invented by God and I can't believe I never owned one until recently. This is a DeWALT 20V Lithium Impact Driver and it came as a set with a drill. I bought this impact driver after a friend showed me the merits of using one earlier this year. I have used this thing to build the chicken run and a thousand other things around here. When you drive a screw with a drill and screwdriver bit you frequently spin the bit out of the head of the screw and strip the slots in the screw head. Not with this baby. It has high torque, low rpm and it hammers the bit as it turns. I have never had it spin out or strip a screw even after thousands of screws and it has so much power it will drive the screw completely through the board you are screwing into if you don't stop. It is loud and it sounds like a impact wrench at an auto garage when they put on your wheel lug nuts but I think it's cool. It also has 'headlights' which I thought was a gimmick at first but now love. It is definitely my most used power tool followed closely by my Dremel 3" hand held rotary saw.