I've found that with National, they'll give you one keyfob and two keys, linked together with one sealed cable. However, occasionally I find a keyring where one key is attached to the cable, and another to the ring on the keyfob, allowing the duplicate key to be removed (and, in my case, put on the ring of the other keyfob that National/Alamo hides in either the trunk, or with the spare tire, or under the carpet/seats, or a similarly hidden compartment of the vehicle that also contains the manual, delivery stuff, front license plate holder, etc...)