854-TX55-150M Apex Torx ® Bit ‘Service Drive’. Apex Torx Screwdriver Bits from Apex Fastener Tools are becoming extremely common in automotive repair and appliance assembly. By design, Apex Torx Screwdriver Bit head screws resist cam-out better than Phillips ® Head or Slotted head screws. Where Phillips ® Heads were designed to cause the driver to cam-out, to prevent over tightening, Torx heads were designed to prevent cam-out. The reason for this was the development of better torque-limiting automatic screwdrivers for use in factories. Rather than rely on the tool slipping out of the screw head when a torque level is reached, thereby risking damage to the driver tip, screw head and/or work-piece, the newer driver design achieves a desired torque consistently. Apex Torx Screwdriver Bits from Apex Fastener Tools are manufactured to the tightest tolerances in the industry, most are even tighter than licensing agreement requirements and all Apex bits meet the most stringent government and military specifications.