Find the Calibration Devices you need for your 2004.5-2005 Chevy/GMC 6.6L LLY Duramax. Whenever you add larger tires and/or change the axle gear ratio you can run into issues such as the speedometer reading incorrectly and erratic transmission shifting. A calibration device is powerful user interface that plugs into the OBD port and lets you recalibrate your speedometer while also restoring accurate shift points and proper function of the electronic stability control. Calibration devices can be exactly what many enthusiasts with lifted trucks are looking for. These devices, or programmers, allow you to electronically calibrate your truck for larger tires, program for a different gear ratio, adjust your speed limiter, read/clear diagnostic trouble codes, and more. Calibration Devices are available for a wide variety of vehicle applications. They easily install in minutes, and some offer the ability of being updated via the internet. Furthermore, they provide the option to return the vehicle back to stock settings if ever needed. Shop all the top brands such as Hypertech, Superchips, and more!