Screwdriver divides according to the power source with Manual screwdrivers, electric screwdrivers, pneumatic screwdrivers.
In batch or head to a Word and a cross.

Screwdriver model is represented as: x pole diameter cutter bar length. For example 3x75mm, it means that the pole diameter 3mm, Rod 75mm (not length). Sometimes write 3 inch screwdrivers pole long 75mm. Some manufacturers in terms of PH2 2#, actually the same. You can based on the thickness of the tool bar to roughly estimate the size of cutter, but industry is on cutter size-specific. Models 0#, 1#, 2#, 3# corresponding roughly to the thickness of the metal rods, 3.0mm, 5.0mm, 6.0mm, 8.0mm.