The jackpot is triggered by a specific combination of symbols on the reels. When you pull the lever or push the button, the random number generator generates a mixture of symbols. If the given combination matches the jackpot combination, you win big time.
Pick Slots With The Highest Return To Player (RTP) Percentage. If you're looking for slot machines that are most likely to hit, a good starting point would be finding ones that have the highest percentage of RTP. This is because the higher the RTP percentage, the more likely the slot machine is to pay out.
