Genuine OEM Hyundai Fuel Filler Cap, part number 31010J9000. This cap is essential for sealing the fuel tank opening, preventing fuel evaporation, and maintaining the correct pressure within the fuel system. It is designed to securely close the fuel filler neck. Constructed from durable black plastic, it includes a tether to prevent loss and a click mechanism to indicate proper tightening. Choosing genuine OEM ensures the correct sealing properties, pressure relief valve calibration, and material resistance to fuel, preventing check engine lights and maintaining fuel system integrity.