MILLIMETER and/or INCH - just a pinch of MM and IN.

The millimetre (American spelling: millimeter, symbol mm) is a unit of length in the metric system, equal to one thousandth of a metre, which is the current SI base unit of length.
The corresponding unit of area is the square millimetre and the corresponding unit of volume is the cubic millimetre.

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Swiss Post Card 144 mm x 104 mm
BLICK NEWSPAPER SEPT. 23, 2007
DigiCollage by Hans Alfred Loeffler

An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. Its size can vary from system to system. There are 36 inches in a yard and 12 inches in a foot. A corresponding unit of area is the square inch and a corresponding unit of volume is the cubic inch.
The inch is one of the dominant units of measurement in the United States, and is very commonly used in Canada. In the US and commonly in the UK, Australia, Canada and New Zealand, personal heights are expressed in feet and inches by people of all ages. In Canada, personal heights are shown in metric units on official documents such as a person's driver's license.