12pc 3/8" & 1/2" Drive METRIC Hex Bit Allen Wrench Socket Set on Snap in Rails FEATURES: This set includes: CHROME VANADIUM STEEL HEAT TREATED PROFESSIONAL QUALITY TOOL THE 3PC 1/2DR HEX BIT SOCKETS HAVE A LOCK PIN HOLE ON THE FEMALE For A MORE SECURE HOLD 3/8 DR. HEX BIT SOCKET SIZES: 3MM 4MM 5MM 5.5MM 6MM 8MM 10MM 1/2 DR. HEX BIT SOCKET SIZES: 12MM 14MM 17MM WITH LOCK PIN HOLE 10 HEX BIT SOCKETS AND 2 SNAP ON RAILS = 12PC