If you are concerned about someone breaking into your car then you might want to protect your key FOB.
By simply wrapping your key FOB in aluminum foil you can prevent a thief from intercepting the signal. If you park your car outside at home then you might consider using a foil-lined container or placing your keys in a coffee can. I’m going to start wrapping mine in aluminum foil when I travel and stay in a hotel. If you doubt that this issue is a serious threat then watch How Thieves Unlock A Car.