The Emarald Green Aluminum Screw-On Air Valve Knob With Stainless Plaque is a durable and stylish addition to any tractor or trailer. Its emerald green finish and large screw-on design with stainless steel plaque make it a standout feature. Sold individually, this air valve knob is a practical and eye-catching choice for those looking to upgrade their vehicle's appearance and functionality. Whether you're in need of a replacement or simply want to add a touch of color to your rig, this product is a great option.