BW&reg; 4Pcs Hex Screwdriver Screw Driver Tools Kit Set for RC Helicopter Aircraft 1.5/2.0/2.5/3.0mm Special tools suitable for different kinds of RC helicopters, aircraft, vehicle Ergonomicallyandslip-resistantdesignedhandleforcomfortablegrip. Compactandlightweightdesign. 4 kinds of hex key size for different needs: 1.5mm, 2.0mm, 2.5mm, 3.0mm.