(10) Extra Long Triple Square Spline Bit Sockets: M4 1/4 Drive (ATD-243) M5 1/4 Drive (ATD-244) M6 1/4 Drive (ATD-245) M8 3/8 Drive (ATD-246) M9 3/8 Drive (ATD-247) M10 3/8 Drive (ATD-248) M12 3/8 Drive (ATD-249) M14 3/8 Drive Tamperproof (ATD-252) M16 1/2 Drive Tamperproof (ATD-253) M18 1/2 Drive Tamperproof (ATD-254) Extra long 4-1/2 shank Bits are made from S2 steel to meet or exceed torque specifications Sockets are made from heat treated chrome vanadium steel for strength durability