Hex drivers to fit electric screwdriver

[jimmy]

Who makes hex drivers with the large hex that pushes into regular electric screwdrivers ???
I saw Matt Benfield with some integy ones I think at the weekend, but can't find them online. anyone know any others? I'm after metric and imperial. I was gonna buy a fancy Hitachi electric driver but might as well save money and use my old black and decker big thing.