I really liked the tiny bit driver. It is really functional and doesn't take much space at all. However, its size made it hard to find when i needed it so i made a simple keychain version. The hole is a tiny bit tighter to prevent bits from falling out while carrying so i recommend scaling the model to 101% or 102% if you want to be able to change bits easily. 
 

I will add the magnetic version in the future if there is demand for it.