Upgrade your tractor or trailer with the Large Chrome Air Valve Knob Glossy Cross Sticker. Available in black, blue, or red, and with tractor or trailer script options, this screw-on mount style knob adds a touch of style to your vehicle. Sold individually, this knob is a practical and affordable way to customize your air valve and add a sleek, glossy finish to your rig. Choose the color and script that best suits your needs and give your vehicle a polished look with this easy-to-install accessory.