3840/1 Hex Plus Stainless Steel Bits. Wera Stainless Torsion bits prevent rust on stainless steel fixings caused by contamination from conventional steel tools. Vacuum ice-hardened to the same strength as conventional steel tools, and so suitable for tough, industrial use. Wera Stainless bits feature a unique Torsion zone, extending bit life over standard bits.Use with Wera stainless Rapidaptor bit holder.Application: For hexagon socket screwsDrive: 1/4in Hexagon, DIN 3126-C 6,3, ISO 1173.Tip: Hex-Plus, similar to ISO 2936, stainless steel