Classic slots or 3 Reel Slots are the most popular slot games in the world - they are an exact duplicate to the first ever slot machine which was invented in 1895.
The classic online slots is a machine with only one payline and three reels. Many of them are very similar and differences pertain only to the theme of the game, they have coin denomination, the same jackpot and number of possible winning combinations the reels can stop on.