Forged from high-grade S2 steel. IRWIN bits are between 58 and 62 on the Rockwell hardness scale. IRWIN offers power drill and impact driver screwdriving bits for just about any application imaginable. Tri-wing, also known as triangular slotted screws, are used in electronics, particularly Nokia phones and some Apple Mac computers. All IRWIN fastener drive bits are manufactured to meet ANSI Standards. Available in a wide variety of point sizes.