This enumerated type contains the list of values that can be used by the seller to set the number of days after item purchase that an unpaid order can be combined with one or more other mutual (same buyer and same seller) unpaid orders into one Combined Invoice order. Either the buyer or the seller can initiate the Combined Invoice process. Sellers can offer buyers shipping discounts through Combined Invoice orders, and buyers only have to make one payment for multiple orders as opposed to a payment for each order.