Splits refers to the way you split up your tickets when selling more than 1 in a listing. You can choose to sell them in several combinations.
• Sell any quantity, but don't leave me with a single ticket: The system makes sure 1 ticket isn't left over, but lets buyers buy several tickets at once
• Multiples of 1, 2, 3, 4, etc.: You set the number of tickets to sell together
• Sell all my tickets together: You don't split up your tickets at all
If you're selling more than 2 tickets in a listing, it defaults to Sell any quantity, but don't leave me with a single ticket.
Otherwise, it defaults to Sell all my tickets together.