RC TOOLBOX MUST HAVE - Four hex nut drivers with socket sizes of 4mm (M2), 5.5mm (M3), 7mm (M4), and 8mm (M5). NON-SLIP: More than making a good-looking nut driver, great metal knurling on handle enables better grip. VERSATILE: These thin-walled nut drivers are applicable to assemble/disassemble RC vehicle/helicopters, FPV equipment, electronic components, and household appliances. Length: 6.8 inches (173mm)