The "reels" in a slot are the vertical lines (or rows, if you will) displayed in a slot. The reels contain various symbols that combine with each other on each and every spin to form possible winning combinations. The number of reels can vary depending on the slot, but most slots have at least three reels. The more reels a slot features, the more complex its paytable can be and the greater the number of possible winning combinations. Reels are an important part of online slots and contribute significantly to their allure.