Mileage blocker is a device that can be installed in vehicles to prevent the odometer from displaying more mileage than what has actually been driven. This means that it will block any additional miles added to the car’s odometer, making sure that its true mileage remains intact and accurate. The Mileage Blocker is an ideal solution for those who want to protect their vehicle’s resale value by preventing higher-than-actual mileages being displayed on the dashboard.