Hypertech 32001 Max Energy Power Programmer for 2001-2005 Duramax 6.6L 3-Stage power tuning; tow safe in all power levels up to maximum GCWR Speedometer/odometer recalibration for non-stock tires and rear end gears (not available on all vehicles) Reads and clears Diagnostic Trouble Codes (DTC's) Internet updateable Features easy plug and play design