Screw on the fuel tank cap TYPE: THREADED SCREWS THREAD: M4 X 0.7 DIAMETER: 4MM LENGTH: 20MM HEAD: CYLINDRICAL HEAD DRIVE: ALLEN SURFACE: POLISHED MATERIAL: STAINLESS STEEL QUALITY CATEGORY: NO QUALITY CATEGORY SEAL/WASHER: WITHOUT SPECIALTY: HEAD DIAMETER 10 MM FOR SAFETY WIRE: NO LENGTH: 6.5MM