Inventory Items allow guests to buy additional items either through the MyPMS system or online (if enabled).  You should add Inventory Items for every item/service that your property offers that is not already covered by an existing item, and make some available to sell online, if desired.

If you are selling Items online, via your Booking Engine, and the guest books multiple rooms with one or more Items, then BookingCenter will place all Items booked on the first booking in the series, ie. the -1X booking. If necessary, this will require a staff member to remove the Item(s) from the first booking and apply the correct quantity to the additional online bookings (-2X, -3X, and so on) in the appropriate amount.

We do this because it's impossible to know how many Items are to be placed on each booking when multiple bookings are booked at once.

For adding Inventory Items, please review the MyPMS Reference Manual (https://docs.bookingcenter.com/display/MYPMS/MyPMS+Online+Documentation) in the section titled Setup | Parameters | Inventory Items found at: https://docs.bookingcenter.com/pages/viewpage.action?pageId=1376627