Chrome Brass Knuckle Tractor Trailer Air Brake Knob *This product cannot be shipped to Canada. Add a rough-and-ready look to any cab with these brass knuckle air brake knobs! Brass Knuckle Air Brake Knobs Available With Tractor And Trailer Scripts (Choose Option Above) Made From High-Quality Chrome Aluminum Unique Scripted Design Attaches With Set Screw Dimensions: 4-1/8" (L) x 4-3/8" (W) Quality Made Product California Prop 65 WARNING: This product may expose you to a chemical known to the State of California to cause cancer and birth defects or other reproductive harm If you should need additional truck parts and accessories, please don't hesitate to call our toll-free number: 1-888-888-7990