A light on the machine that flashes to indicate that there is a problem with the machine.

In electromechanical the storage area for the coins that are transferred to the tray when a player wins.

In video machines the indicator that displays the credit balance of the player.

The slot machines with mechanical moving reels powered by electricity.

The first video slot machine invented by Fraley in 1975.

The first slot machine invented by Fey in 1887.

Slot machines that offer lower payouts but have a larger number of winning lines.

The first electromechanical slot machine invented by Bally Manufacturing in 1964.

The Random Number Generator, which is the software that generates the random combination of symbols in video slots.

The number of symbols in each combination. Slots have either three reels or five reels.