In the past few years, we have covered plenty of iPhone compatible car engine immobilizers here. The BT-25HD4.0 is also worth a look. It is a car security device that combines with your smartphone to stop theft. Without a valid Face ID or Touch ID, your car simply won’t start.
The device automatically arms 3 minutes after your car is turned off. It can pair to 5 smartphones for easy car sharing. It also has a valet mode. The BT-25HD4.0 is suitable for BMW, Audi, and various other popular cars.[where to get it]