It is a professional precise reversible screwdriver set, which includes 8pcs different types of double ended screw drivers. It allows you to open cover of mobile phones without damaging phone cover. Light weight. Very convenient to carry. HIGH QUALITY MATERIAL: Chrome-Vanadium Steel with heat treatment,high hardness and good toughness. Not only is the plastic exterior coating high temperature resistant but in addition it provides a generalized weather protective coating. LONG DRIVER BITS: The screwdriver set is with 8 pcs 110mm/3inch highly precise long driver bits in various specifications , removable and installable, to meet different work needs. EASY TO USE & ADJUSTABLE BITS: Each screwdriver bit fits perfectly onto the handle, and easily be changed from one to the other, so easy switching from different screws. MULTIPURPOSE USE: Professional repair tools to assist devices repairing (Mobile, PC, Tablets, Camera, Watch, Small Appliances). Professional portable hardware tools with perfect weight & compact design. The CR-V bits which are made of chrome vanadium and strong magnetic properties have a hardness level of 52 – 56 HRC, making them ideal for any professional repairing service. Compatibility: It is compatible with most devices from various brands. Adjustable length of screwdrivers/bits hardness: 52-56hrc – material: chromium-vanadium steel. Precision machined cr-v bits made of chrome vanadium with strong magnetic properties PH#000 (-)1.5 mm PH#00 ~ (-)1.8 mm PH#0~(-)2.5mm mm T5 ~ T6 mm T8 ~ T9 mm Y#00~(-)AWL1.5 mm Y#0~star2.0mm mm H1.5mm~H2.0mm