Chrome vanadium steel, contents:6 pcs 1/4 dr: t10, t15, t20, t25, t27 and t30, 5 pcs 3/8 dr: t40, t45, t47, t50, t55 and t60, 1 pc adapter reducer: 3/8(f) to 1/4(m), 1 pc socket holder, weight: 1 lbs