1.The 13 piece socket set includes chrome vanadium steel forged socket and S2 forged steel forges for torque, strength and durability. 2.Dr. Bit 1/4 "Sockets - Chrome vanadium chrome sockets provide maximum resistance to oil and corrosion bit S2 forged, heat treated steel drill bit for torque, strength and durability, 3. 3/8 "Dr. Bit Sockets - Chrome vanadium chrome sockets provide maximum resistance to oil and corrosion bit S2 forged, heat treated steel drill bit for torque, strength and durability 4. 1/2 "Dr. Bit Sockets - Chrome vanadium chrome sockets provide maximum resistance to oil and corrosion. Forged, heat treated S2 steel drill bit for torque, strength and durability. 5.Package Includes - All pieces in this set store nicely in a durable blow-molded carrying case for easy organization and convenient portability.