Bank note

A bank note is a bank certificate that represents an item or stack items of the same type. It is equivalent to actual items, but cannot be used physically until exchanged for an object, in a bank.

All tradeable items can be 'noted' and 'un-noted' in a bank. This is useful for players who wish to trade large amounts of items at a time. They are also usefull for training magic or simply converting the items into coins via the low or high Level Alchemy spells.

Trivia
In Runscape Classic, you could only get certificates for select few items, and only shops that sell or buy the item can uncert it for you.