The CURT Echo in-line trailer brake controller is a Bluetooth enabled device that wirelessly connects to your smartphone and allows you to control and monitor all trailer brake activity right from your device. The Echo brake controller brings your towing experience into the modern age. Powered by Bluetooth, it wirelessly connects to your smartphone without any extra modules required. Simply download the Smart Control app on your Apple iOS or Android OS device, plug the Echo into your vehicle behind the existing 7-way RV blade socket and you're ready to start towing (USCAR connection required). The app allows you to create multiple trailer profiles for different towing situations. The CURT Echo in-line brake controller operates with a tri-axis circuit for smooth stops going up or down a hill, and it is able to operate up to two to eight trailer brakes at a time (one to four axles). It is also compatible with cruise control and ABS brakes.