Some sort of bit holder in cordless drill set.

I just got my first ever cordless drill and in the 'free' kit were two bit holders which I haven't a clue what the use might be.

There is a coil spring tucked inside along with what appears to be a 'tabbed washer' on the other end.

Dimensions: 14mm diameter (external) and about 28.5mm height.

No description in owner's manual.  Thanks for help.