867/4 Z TORX® BO bits with bore hole, TX 25 x 70 mmPremium bits for TORX® BO socket screws. TORX® BO screws have a protruding pin in their drive profile. This prevents unauthorized loosening, as these screws cannot be operated with ",normal", TORX® tools. Only special TORX® BO tools have a bore which can mount the pin. Tough, for universal use. 1/4", hexagonal, suitable for holders as per DIN ISO 1173-F 6.3.