23 pcs ratchet screwdriver bit and socket set 1.Material: stainless steel ,or CR-V steel 2. ... steel or S2 3. Surface treatment:eletrodeposited chromium, and sand plasting4.Function and feature:screw driver use computer repairing5.Case size: ... extension bar can be extend t 150mm9 pcs carbon steel socket(with out heat treatment) : 5,6,7,8,9 ... s q'ty:11900 set 23 pcs ratchet screwdriver bit and socket set