There are various types of accumulator bets. Some of them are more common among the clients, including doubles, triples, and Lucky15. The first two types are easy to explain. You must combine two bets with your double and three with a triple. Regarding Lucky15, it should contain four selections. However, this accumulator type should cover 15 bets, including singles, doubles, trebles, and a 4-fold accumulator. If one selection wins, you get a return.