1/4 Inch Security Bit Driver and Bit Set with Case, 37-Piece The Tekton 37-Piece 1/4 inch Bit Driver and Security Bit Set is an essential screwdriver set for security fastener applications, offering a complete range of security hex, star, clutch, and spanner bits.. The bits are made of S2 steel with a zinc-phosphate coating that resists corrosion, and theyre designed to be longer than standard bits to improve your access to recessed fasteners.