Patented bit holding system forces bit surface to opposing side for maximum bit retention - strengthPackaged in patented impact resistant "slide rail" system Heat treated socket bases for durability and service abilityChrome sockets; S2 and alloy steel bitsIncludes E4, E5, E6, E7, E8, E10, E12, E14, E16, E18, E20, E22 and E24 Torx® Sockets 13 Piece External Torx® Set (1/4", 3/8" and 1/2" Dr.) includes: E4, E5, E6, E7, E8, E10, E12, E14, E16, E18, E20, E22 and E24 Torx® Sockets packaged on a clip rail