A regular slot machine was a mechanical device that had several spinning reels. These were usually powered by a lever on the side of the machine. The reels had various designs or pictures painted on them. The reels spun around in the event the lever was pulled and in the event the right combination came up the player was a winner. The lever gave rise to the popular American slang term: one armed bandit.

These machines were the first coin operated gaming devices marketed and are still among-the most popular. Most casinos now feature large banks of them and also the gaming industry now derives most of its revenue from devices for example fruit machines.

In some places; such as most of the US and Canada, these machines are limited to licensed casinos and other learn online gambling halls. In other areas such devices could be found in almost any public place including bars, pubs, amusement arcades and bookmakers shops.