A non-standard unit of measure is a specified amount that is used repeatedly to indicate the length or mass of an object.

Units of measure are "non-standard" if they are not commonly used by most people. Units of measure are standard if they are used by most people.

1) I can measure the width of my desk by using my hand span. My desk is 10 hands wide.

2) Erasers of uniform length could be used to measure the length of one's foot and to express the length in terms of erasers.