A unit stack gadget, or ULD, is a bed or holder used to stack baggage, cargo, and mail on a wide-body flying machine and, in general, a restricted body air ship. It allows large quantities of payload to be packed into a single unit. As this causes fewer units to stack, it spares the opportunity of ground teams and additional exercise and counteracts delayed flights. Each ULD has its own pressurized rundown (or display) with the aim that its substance can be followed.