I am guessing that you, like most people, touch the steering wheel while getting out of the car. Just the slightest turn of the wheel will lock the steering. Your new key that comes with the tumbler will look exactly like your original key and will fit all of your door and trunk locks.

It is possible to buy an after market tumbler with key. The after market tumbler is not the same quality as Mercedes and the key will not fit your doors or trunk. Usually the cost is below $75.