Neo Products Usa Inc (Set of 2) Smart Parking LED Garage Flashing Warning Stop Sign - Bumper Sensor,Red (Set of 2) Smart Parking LED Garage Flashing Warning Stop Sign - Bumper Sensor. Just park this stop sign in your garage LEDs will automatically flash if your vehicle's bumper taps the pole. Height adjustable up to 4 feet, and weighted non-slip base for extra stability. Each sign comes with base, poles, connectors, and 2 button cell batteries.