10 pc set + Rail = 11 pcs total. Set includes 1/4″ Drive – T-10, T-15, T-20, T-25, T-27, T-30 3/8″ Drive T-40, T-45, T-47, T-50. This 11-piece set includes both 3/8″ and 1/4″ drive sizes, designed to fit a range of fasteners with its specialty star stubby design.