The 54 Hollow-ground flat bits range in size from .120x.020 to .360x.070, and includes doubles in the thinnest sizes. The set also includes a complete selection of Phillips, Allen, and Torx bits to cover scope rings, bases, recoil pads, and the like. The difference in the basic set and the professional set lies in the 15 ingenious specialty bits that are included in the professional set. Comes with two handles made from comfortable overmolded plastic. The first is a regular size handle thats good for most jobs, and the second is a slimmer, shorter Close Quarters handle that is good for finesse work with smaller bits. Also comes in a durable custom box thats ready for the bench or your range kit.