The drive head is made of high-speed steel, resistant to stripping breaking,has a long lasting performance.The wrench size is engraved on each handle for easy identification, high strength and anti-rust.Used for disassamble Hex Screw in helicoptor and other place.Ideal used for most rc car, rc boat, rc helicopter, rc quadcopter, multi-axis FPV racing drone, hobby Car quadcopter, airplane, helicopter boat models and more.4-Pack 4.0mm 5.5mm 7.0mm 8.0mm hex nut driver. Description: Hex Screwdriver Material: High speed steel Screwdriver handle: Aluminum Color: Black Weight: 170g Specifications: 4.0mm 5.5mm 7.0mm 8.0mm Total length: 175mm The drive head is made of high-speed steel, resistant to stripping breaking,has a long lasting performance. The wrench size is engraved on each handle for easy identification, high strength and anti-rust. Used for disassamble Hex Screw in helicoptor and other place. Ideal used for most rc car, rc boat, rc helicopter, rc quadcopter, multi-axis FPV racing drone, hobby Car quadcopter, airplane, helicopter boat models and more. Package List: 1 * RC repair tool 4.0mm hex nut driver. 1 * RC repair tool 5.5mm hex nut driver. 1 * RC repair tool 7.0mm hex nut driver. 1 * RC repair tool 8.0mm hex nut driver.