# Units

Units are the canonical description of tradable goods. They are manipulated by mints, and represent the goods and currency carried by purses and payments. They can be used to represent things like currency, stock, and the abstract right to participate in a particular exchange.

# Labeled extents

Units are labeled extents. To be specific, units are a record with two parts: a label, which identifies an assay, and an extent. The balance of a purse or payment is in units. For example, the balance of a purse might be 3 bucks, written in units as:

{
  label: {
    allegedName: 'bucks',
    assay: bucksAssay,
  },
  extent: 3,
}