The United States has an on and off history of attempting to convert to a nationwide use of weights and measures in the country from the United States customary units (i.e. the use of feet, inches, and pounds) to what is known as the International System of Units which uses units such as centimeters, meters, and kilos.

It's not kilos, it's Kilograms. Kilo is not a unit, it's a multiplication. I know in everyday use these are used interchangeably, but it's just not a unit.