This Road King Truck Parts fuel cap is a must-have for any commercial truck owner. The cap is made of high-quality aluminum material, which makes it durable and long-lasting. It fits perfectly with a 3 1/2" Course and prevents any unwanted spillage or leakage. This cap is vented, allowing air to pass through and prevent any pressure buildup. The lock feature ensures that the fuel tank is secured and tamper-proof. This fuel cap is compatible with a wide range of commercial truck models and is a perfect replacement for old or damaged caps.