Wiha picofinish ball end hex screwdrivers imperial sizes wiha 00538 an imperial sized wiha picofinish ball end hex screwdriver the screwdriver has a handle with a rotating cap and rapid turning zone it is ideal for high precision work with electro technical and precision components the ball end enables the user to work at angles up to 25deg wiha 00538 picofinish ball end hex screwdriver 318mm 18