Japanese made, chrome vanadium, steel engineer's screwdriver with the blade extending continuously through to the striker pad. This allows the tool to be struck with a hammer to assist with loosening fasteners. Shank is square section to allow...
These screws need a jeweler's screwdriver or similar - round Phillips head. Metric dimensions are nominal and specified as Overall Length x Shank Diameter Under Head x Head Diameter. See below for size and gauge code.