This is a remix of a model by @LoboCNC. The original screw holder is quite universal: it fits many hand screwdrivers as well as standard hexagonal bits.

My problem was that I have some short hexagonal bits that I still wanted to use but the standard round extender they fit into was too big for the original screw holder.
This model is slightly larger than the original. Just making a round hole left walls that were way too thin.
You don't have to choose one of them: print both and all your needs will be addressed .
The author remixed this model.
Reshaped and enlarged a bit to fit a round bit extender.