Some cordless drill drivers have storage areas built-in, which are used for holding drill or screwdriver bits when they’re not being used. This usually consists of a simple clip that holds the bits, or sometimes a magnet as well.
What are the advantages of on-tool bit storage?
There is less chance of bits getting lost as you will always know where to find them.
There is no need to hold bits or keep them in your pocket when working.
It allows for quick changing between different bits.