The types of keys are : 1) Grand master key
2) Master key
3) Sub Master Key
4) Individual key or Guest key
5) Card key
6) Electronic key

Choosing a hotel room category can often be a daunting task, especially when you don't know what the individual room-type descriptions mean.
Here is a quick run-down on common room categories in the United States, the Caribbean, Canada and Mexico:
STANDARD (std):This category usually means the most basic roomtype offered by the hotel. It has basic, standard amenities and furnishings. A standard room in a Four Seasons hotel is without question much more deluxe than a standard in, say, a Holiday Inn, but there may be higher categories from which to choose. Standard rooms in hotels with higher categories often have no view or have a poor view over the dumpster or parking lot.
MODERATE (mod):Usually a slight bit better than standard, but still not deluxe. It may refer to the room view as well as the size and type of furnishings offered.
SUPERIOR (sup):This category is always subject to interpretation. It's supposed to mean superior to a standard room in both size and furnishings, but it often refers to just the view. Some hotels have only Superior rooms; the categories then are defined by the view and location of the room.
DELUXE (dlx): These rooms are supposed to be Deluxe in every way: View, location, furnishings and size. In some Caribbean hotels, however, a deluxe room is a lower category than a Superior, so it's wise to question your choice before final booking.
RUN OF HOUSE (roh): This can mean anything the hotel wants it to mean, but typically the interpretation should be "standard room or better at time of check in; any location within the hotel." With the exception of upgrades to suites or junior suites, this category often does not distinguish between Standard, Superior or Deluxe. It does NOT mean,