Features chrome plated castings with brass internal parts for long life. Swivel dual foot chuck inflator. For use on motor homes and other vehicles with smaller dual wheels WARNING: For best results, check tire pressure when the tires are cold or when the vehicle has not been driven for several hours. Readings taken after prolonged driving at high speeds will increase tire pressure causing a false reading. Check tire pressure at least once a week or as necessary. Consult your owner's manual for the recommended air pressure for your tires. These gauges have been accurately calibrated and inspected. For continued accuracy, take care of them as you would any precision instrument.