Im selling this box becouse we need the money. It is in great condition! has been on the truck less then a year. It is for a 04 LLY. you can go to Had it sold but the guy didnt have a LLY duramax so its back up for sale. Need to sale make offer! Thanks Asking 500. OBO New you will pay --- $878.75 40-125 horsepower increase increase gas mileage by 2-3 miles per gallon, and much more... COMPLETE INSTRUCTIONS used IN BOX Level 0: Stock Level 1: 40 Horsepower - 100 Foot Pounds of Torque Level 2: 60 Horsepower - 120 Foot Pounds of Torque Level 3: 75 Horsepower - 170 Foot Pounds of Torque Level 4: 90 Horsepower - 200 Foot Pounds of Torque Level 5: 125 Horsepower - 240 Foot Pounds of Torque If you are looking for the power or just fuel economy this is what you need.