Apex nutsetters are used for fastening nuts and bolts with a power tool. They are offered in both magnetic and non-magnetic versions and feature awesome rigidity and concentricity. Think of them as as a small socket with an extension attached, but all one piece. Apex nutsetters are 6 point tools and are offered in both metric and standard sizes. Various lengths are also offered. They can accomodate nut and bolts ranging from 1/4" up to 1-1/8" in SAE and from 6mm to 12 mm in metric. . Shank sizes offered include 1/4", 5/16", 3/8", 7/16", and 5/8".