This is about a set of two keys:

One new transponder key, with the chip included inside the key's head, tested and ready to be programmed. And a second dummy key as a gift just to open doors and trunk. You'll save a lot of money and time if you keep this dummy key in your wallet to open up the car in case of a lockout.

You will need to take your actual working key with this new set of keys to a professional locksmith shop or the dealership to get these new keys cut to fit your vehicle.

Once you got both keys cut, you will need to get the transponder key programmed to your car.

That could be done by yourself. With the item you'll receive the programming instructions. Is a very easy procedure you can follow step by step. All you need to have is two original factory working keys to do it.

If you don't have two original working keys, you will need get this new key programmed at dealer or professional locksmith. 

Keep in mind that once you get this new key programmed, you'll be able to use it with your old working key to program more keys yourself.

The dummy key does not need programming since is only for doors and trunk.

It fits:

(2011) Ford Explorer