This bet type is used when you wish to play safe. So the total funds get split into two equal parts. One is used to bet on a horse that will most likely win according to your thoughts. And the other — that same horse will finish on any place from the 1st to 4th (sometimes 5th or 6th). This means that even if your horse does not win, most likely it will finish within the bet range and you still get something from the race.