Pictured above is the actual unit for sale. This is the last bracket of this type I can find and my supplier no longer carries it, so this may be a closeout on this configuration. Altogether, the suction cups are rated at 400 lbs for peace of mind when mounting outside the car, but the bracket plate has holes for tethering. The bungy cord is for attaching to the bracket arm and to a hard point to dampen vibration.
Pictured below are just a few of the various mounting options...