this 4 way pin vise has 2 double ended collets sizes from 0mm to 3.2mm or about 1/8"
it is ideal for using those small drill bits or maybe working with a 3mm burr on plastic when the speed of a small drill will be to harsh and melt the thing you are working on.
it is a good "dofor" tool even for may be holding some wire
one of those invaluable things you will not be able to do with out