A conventional slot machine was a mechanical device that had several spinning reels. These were usually powered by a lever on the side of the equipment. The reels had various designs or excellent online casino 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 very first coin operated gaming devices marketed and are still among-the most popular. Most casinos now feature large banks of them as well as the gaming industry now derives most of its revenue from devices for example fruit machines.

In certain places; for example a lot of the US and Canada, these machines are restricted to licensed casinos and other gambling halls.