Bounding

Bounding is the ability to summon creatures that a character previously marked. However, bounding can also be used with items as well in order to bind those items and summon them at any point. The number of binds you can have is determined by the rank of bounding you have, which also determines the max size of your binds.
  Level I:
Your binds can only be about the size of a medium bird and weigh up to 10 pounds (4.5 kilograms). A level I bind takes up 1 slot. You only have 1 bind slot.   Level II:
You can one bind up to the size of a typical adult human and about 100 pounds (45 kilograms). A level II bind, however, takes up 2 slots. You have 2 bind slots.   Level III:
You can have one bind up to the size of a large, adult horse and about 1000 pounds (500 kilograms). A Level III bind takes up 4 slots. You have four bind slots.   Level IV:
The world is your oyster. You can bind things up to the size of a simple family home and about 100,000 pounds (45,000 kilograms). These binds take up 8 slots. You have 16 bind slots.