Although in the U.S. there is a standard size for an infant bed (~71 cm x ~133 cm), 12% of the 2.4 million infant beds sold annually are not of this size; "mini cribs" are an example of this. The "mini crib" is an umbrella term that covers all cots smaller than the standard size. It means that travel cribs and many play yards can also be called mini cribs. This said, people often use the term for small baby beds with hard sides.