Set of 6 pieces. The square shank allows use of a wrench so more torque can be applied. Alloy steel shank (chrome-vanadium), the highest-quality material known for screwdrivers. Black tip prevents any material shedding in critical productive processes (food industry). Ergonomic design provides greater grip comfort. Exceed ASME B107.600, ISO 2380-1 & ISO 8764-1 standards. Screwdrivers sizes: Phillips: PH0 x 2-1/2”, PH1 x 3”, PH2 x 4”, PH3 x 6”, PH4 x 8”, PH2 x 1-3/8”.