Class III gaming regulations govern most slots and casino table games like RNG slots, blackjack, craps and roulette. This means that according to the classifications, Class II slots aren't truly slots. Unlike Class III slots or Vegas-style machines, they are really electronic bingo games with a slot machine interface.
Class II gaming regulations governs the game of Bingo. All recognized tribes can offer bingo games, as well as electronic equipment that helps facilitate the games. Class III gaming regulations governs most casino gaming, including blackjack, craps, roulette and, yes, slot machines.