My Mercedes key looks like this below and you have insert it and turn to start the carCan I just say I really don't want to be in the desert, 5 days from another human, and have my car decide it no longer accepts my bluetooth phone key. Thanks Ineos for giving us a real key!
My car wouldn't start recently and it took a while for me to catch on that it was because the battery in the key was flat.
I don't carry spare key batteries or the spare key but luckily there were shops hat sold batteries about 500 metres away.