I would not recommend the Invisibrake by Roadmaster.
We had one put on our car (Chevy HHR) it didn't slow or stop the car, the brake rotors didn't even get warm! This is how we found out it didn't work. We bought it from a well known RV company in Chattanooga, TN. When we went to get our car, we were told they had not test driven the motorhome and car in tow. They said I could get a feel of the braking ability on the car and motorhome by making a few stops and adjust the brake pressure as needed. To make a short story, my wife and I tested the the car on a slight hill. I tied a long string to the break away pin, and asked my wife to only steer the car. I took the string, she released the brake and when it picked up some speed, I pulled the break away pin and it rolled to the bottem of the hill.
Short story, the manager said "it works as designed and I was leagle"! Time went by, Invisibrake was taken off car, got refund.
It was installed on 9-23-2011.