05060048001 Wera 867/4 Z 1/4'' Hex Torx BO Bits with Bore Holes is for recessed TORX® screws and have a protruding pin in their drive profile. This prevents any unauthorized loosening since the "normal" hex tools cannot move these screws. Only special BO tools have a bore hole to take up the pin. Wera 867/4 Z 1/4'' Hex Torx BO Bits with Bore Hole are suitable for holders as per DIN ISO 1173-F 6.3 and has a tough viscous for universal use.