FenSens is a license plate based smart wireless parking sensor on your smartphone. It's an affordable UPGRADE for ANY Car installing in less than 5 min, with no wires, and includes a hands-free App (Android/iOS) that launches instantly providing convenient audio, visual, and vibration alerts when objects are detected in front or behind your vehicle. 

https://fensens.com/collections/feature-collection/products/european-smart-wireless-parking-sensor