Hexagon Screw Drive metric set 4 pcs. High quality / must have tool for RC Helis this kit comes with four hex drivers including 1.5mm / 2.0mm / 2.5mm and3.0mm.Available from CNC handle is anodized in a different color to visualize difference in hex sizes.Perfect grip size, this tool comes highly recommendedThese Hex drivers are available from Align ( Maker of the Trex ). Also, you may choose to order the 2 set only from align which includes only the most common 2.0 and 3.0mm drivers.