Tamper-Proof Torx. Bits have a retaining ring notch made from rugged S2M tool steel to fit all standard multi-bit screwdrivers and power drills. Their 1/4-in. hexagonal body is custom heat-treated to offer strength and durability, and is manufactured to ensure accurate fit and full fastener engagement.Torx. is a registered trademark of Acument Intellectual Properties, LLC.