6 pcs go-through screwdriver set, material:40cr, 1pcs sl5.5*75mm, 1pcs sl6.5*100mm, 1pcs sl8.0*150mm, 1pcs ph1*75mm, 1pcs ph2*100mm, 1pcs ph3*150mm,A screwdriver is a tool, manual or powered, used for screwing (installing) and unscrewing (removing) screws. A typical simple screwdriver has a handle and a shaft, ending in a tip the user puts into the screw head before turning the handle.