Pro Series 54 Bit Driver Kit (Screwdrivers) One awesome kit makes sure you'll have all the driver bits you need for your project. The comprehensive standard in precision screwdriver bit sets, features 54 carefully selected bits. 54 different 4mm bits, plus a 1/4" Adapter to use the bits in standard drivers. Magnet tipped aluminum driver with rubber grips. Flexible shaft extension with magnetic tip.