Allen Key to Hex Driver handle adapter - a DIY Du-Bro

I saw Qrome's "Hex Driver Handle with Grip" a few days ago and thought what a great idea, but, perhaps, I can make a good design even better - you be the judge.

This design is extremely strong - the solid handle has a groove to take the full turning force of the allen Key, while the hole through the tip's centre gives virtually zero slop.

I find these as good as my Xcellite hex driver, and better than my DU-Bro Hex Drivers, as they have a bigger diameter so I can tighten things that littl