Note: If you purchased a new TT-400 System from us or an authorized TireTraker™ Dealer and would like to upgrade, Please call us at 866-200-9773 to order. We will send you the new TT-500 Monitor & Power Cord for $239.00 along with a self-addressed envelope to return the TT-400 Monitor & Power Cord. Once we receive the returned items, we will issue you a credit of $40.00. Your net cost of the upgrade will be only $199.00. This offer is only for customers who purchased a new system.