The amazing EDC-Key by Maratac™ was developed by EOD Robotics in 2008 for use by military robotics repair technicians.
This is an excellent alternative to carrying a multi tool I wrap tape around the outside, and slip this into the sleeve pocket behind my cell phone, along with a set of mini pliers. Along with a pocket knife, this set handles most chores with ease.
Effective, as lightweight as practical, and budget friendly.
Standard bits and extensions fit into the plastic holder very well. The interior of the plastic holder is tapered, in order to hold bits in very well.
I recommend this to my friends, and to all handy-people.