... steel. Surface treatment:Honed Nickel Plated Sockets Rigidity HRC48 79pcs 1/2"&1/4" Dr SOCKET SET :Contents:11PC-SPANNER:8,10 ... ,11,12,13,14,15,16,17,18,19MM(Carbon steel with ... heat treatmentt)18PCS-1/4" DR. BIT SOCKETS: SL4,5.5 ... ,4,5,6, T8,10,15,20,25,30,407PCS-1/4" DR. SOCKETS: 7,8,9,10,11,12,13MM ...