A tool used to twist a screw to force it into place, usually with a thin wedge-shaped head that can be inserted into a slot or notch in the head of the screw - also known as a reamer. It is known as a driver in Shaanxi, Henan and Hubei. There are two main types: the one-letter (negative) and the cross (positive). Also common are hexagonal screwdrivers, both internal and external. What are the screwdriver specifications? What are the screwdriver models? What are the brands of screwdrivers? I believe that everyone will have a screwdriver at home, because the use of screwdrivers is quite large, if the home appliances or wiring accidentally out of order, this time the screwdriver will come in handy, so the home is always equipped with the basic tools is very necessary. Next, I will introduce you to screwdriver specifications, screwdriver models and screwdriver brands.　　One. Screwdriver specifications According to different types of screwdrivers have different specifications, the specifications of a word screwdriver with the width of the bit * shank, such as 2X75mm; cross screwdriver specifications with the size of the bit * shank, such as 3 # X75mm; asterisk commonly used specifications are: T5, T6, T7, T8, T9, T10, T15, T20, T25, T27, T30, T40, T45 T50; the common specifications of the cross are: PH000, PH00, PH0, PH1, PH2, PH3.