Random Number Generator – This is also abbreviated as RNG by most online casinos. This is a type of microprocessor chip that has an efficiency to select few combinations of numbers from amongst hundreds of combinations randomly. The moment you hit the spin option the chip captures the next number or winning combination that is in fact displayed on the spinning wheel. This is technology that is used in most advanced slot machines.

Reels – These are the spinning wheels that spin the moment you click the spin option. They also display the winning symbol or combination. Most machines in the online world offer players with three reel or five reel options.