If you are looking for a compact and easy to carry way to keep whatever type of screw driver you could ever need in your EDC or range kit, check out the QiBit. QiBit is a keychain sized, mini bit driver that accepts common 1/4″ screw diver bits. It is machined from solid 6061-T6 aluminum, hard coat anodized, and retains the bit via an internal o-ring.
One of the most innovative features of the QiBit are its dual angle wrench flats. There are parallel flats for use with a standard 1/2″ wrench or adjustable wrench and angled flats that are perfect for gripping with a multitool.
The potential for a compact driver like this is endless. Your local hardware store probably sells a near endless array of bits. You could pack it with shorter bits for general use and tight spaces or with longer bits for when a bit of extra reach is required. While the intended use is EDC, I would love to have something like this in a compact range kit that could be used to keep a carbine up and running during a carbine course without taking up much space.