The Hypertech 3350 is a device that recalibrates your vehicle's speedometer to accurately reflect new tire sizes or rear gear ratios, correcting speedometer readings after modifications that affect vehicle speed. It features a user-friendly color screen, the ability to read and clear diagnostic trouble codes (DTCs), and connects directly to the vehicle's OBD-II port for easy installation. Key Features Speedometer Recalibration: Corrects speedometer readings when you install non-stock tire sizes or change the rear gear ratio. Color Screen: A large, 4.3-inch full-color screen with simple navigation allows for easy installation and feature changes, even in direct sunlight. Diagnostic Tool: The device can read, display, and clear diagnostic trouble codes (DTCs), which is a helpful function for identifying other vehicle issues. Simple Installation: It plugs directly into the vehicle's factory OBD-II port and uses a USB cable and included software for programming. How it Works Plug In: Connect the Hypertech 3350 to your vehicle's OBD-II port. Select Options: Use the color screen to select the new tire size or gear ratio. Program: The device will reprogram your vehicle's computer to match the new configuration, ensuring accurate speed and shift points. Why You Need It When you change your tires or rear gear ratio, your vehicle's computer doesn't automatically know the new speed. A speedometer calibrator like the Hypertech 3350 corrects this discrepancy so your speedometer shows your true speed.