HI MATTHEW. SOMETIME SOME ROOM KEY CARD CAN BE USED AS A SLOT CARD. TO IDENTIFY THE DIFFERENCE THEY WOULD BE A PERSON;S NAME AND REGISTRATION NUMBER COMPLETED BY THE CASINO. AS AND EXAMPLE; THE DESERT INN CARD THAT IS A ROOM KEY CARD WAS USE AT ONE TIME FOR SLOT CARD. A SMALL THING TO ADD ABOUT THE DESERT INN CARD YOU POSTED IS THAT THE ONE THAT WAS USED AS A SLOT CARD HAT THE INITIAL ITT UNDER THE LAS VEGAS NAME ON THE OBVERSE SIDE (FRONT) OF THE CARD. JUST WATCH FOR THOSE DETAILS IF YOU ARE INTERESTED IN COLLECTING SLOT CARDS. SEE YOU IN VEGAS NEXT JUNE AT THE SC&RCK BOOTH. PAUL - FANTASTIC CANADIAN RETIREE - CASINO ITEM COLLECTOR.