It's both a Programmer and a data/digitial gauge display! The Evolution CTS3 reprograms your vehicles stock computer through the OBDII port of the vehicle. The Evolution is used to save the stock files from the vehicles computer and then upload the Edge calibrations into the vehicles computer. This product comes with multiple power levels custom tuned by a whole team of engineers, and can be installed in minutes without ever popping the hood. The Evolution greatly increases horsepower and torque and not only does it re-tune your vehicle, it stays mounted in the cab of the vehicle and features real-time, monitoring of vital engine and vehicle data for a complete gauge package. If you're looking for a product to improve throttle response, that extra power when towing, race down the track, increase fuel economy, or to just improve the overall driveability of your truck then the Evolution is the option. Not only do you get these increase performance features but you get a monitor that offers a clean simple solution for gauges like EGT (exhaust gas temperature), Boost readings, transmission temp, load percent, percentage of fuel left, and more with the expandability to even add more with our EAS (expandable accessory system) or Edges backup camera. Sleek slim line exterior design with a 5 inch full-color, full screen display with true swipe screen technology. Top notch graphics, great resolution so its easy to read. And it can update through WiFi. Best of all if you need to it saves your factory settings and returns easily to stock. Requires PCM unlock in order to tune. Included in the purchase of your Evolution CTS3 PCM Swap kit is a free cross-shipment of an unlocked PCM directly to your door so you don't have any vehicle downtime. The first step is to fill out our PCM swap web form that will require some information from your truck like the VIN and calibration ID as well as product information like your serial number found on your CTS3 device. Then Edge will send you the unlocked PCM. When you receive the unlocked PCM, simply install the new unlocked PCM, and send back your core to Edge with the included return shipper label. Return shipper label only provided in domestic US shipments.