This bit-set is intended to be clipped to your belt. You can pull the 20 bits out (similar to a measuring tape). Pushing the button makes the bits retract into the casing. It works, though its a bit bulky (80mm in diameter and almost 35mm thick).
I was not sure if I should post this here in the Cheap n' Cheerful section as it seems entirely functional. However, conditions where this is really useful (you move around a lot and use tons of different bits) seem uncommon to me.