Valve Stabilizers for Alcoa Wheel Size: 19.5" • Diameter Hand Hole: Custom • Hole Position: CenterNOTE: Proper Air Pressure is the Most Important Factor in Lengthening Tire Life • The Alcoa Extension and Stabilizer Kit Allows Access to the Inner Dual Tire Valve and Properly Positions and Supports the Extension for Servicing • The Stabilizer Reduces Road Vibration on the Extension and Practically Eliminates Valve Stem Breakage Caused by Vibration