Convert from arms-length to U

Unit Definition (arms-length)
An Arms length is standardized as a unit of distance equal to approximately 70 centimeters, or 28 inches. An arms length is the same as the modern Italian Braccio and very similar to the Turkish Pik.

Unit Definition (U)
The U is a unit of distance used to measure the height of the standard racks in which audio, video, or computer components are mounted. 1U is equal to 1.75 inches (44.45 millimeters), so that, for example, a 2U component is 3.5 inches high, and a 22U rack houses a stack of components 38.5 inches high.