First, note that this is a 7/16" hex shank, not the 1/4" hex shank you would typically find at large stores or hardware stores. This particular extension is of very limited use, and if you're just looking for a standard "Hex-Bits" extension, this isn't for you. If you already know exactly what it is, read on to get an overview. I usually use Irwin for hex extensions because the locking mechanism works - MAGBIT is the only other brand I've found that is as good as Irwin. . With many otherβ¦