You need these (even though you don't know it yet)
June 2, 2016
We put these on the rear mount of our Viper bike trays. Without this lock, someone could unscrew the rear of your bike tray and possibly pry the entire thing off the top of your car. With these, the front and the rear of your bike trays are secure.
Pros:Cost effective. Function perfectly. Additional security for your valuable bikes.