Convert from mark twain to braccio [Italy]

Unit Definition (mark twain)
The mark twain or twain is an old word for the number two, derived from the Anglo-Saxon twegen. The American author Samuel Clemens (1835-1910), who had been a riverboat pilot on the Mississippi in his youth, took his literary name from a traditional riverboat phrase "mark twain", meaning "exactly two" fathoms of water. This was the minimum depth needed for the boats to operate safely without running aground.

Unit Definition (braccio [Italy])
The Braccio is a traditional Italian measurement of length. The word means "arm", and a Braccio is approximately equal to the length of a man's arm, about 27 or 28 inches (68-71 centimeters). In modern times, the Braccio has become an informal metric unit of exactly 70 centimeters (about 27.56 inches), which is the same as the Arm Length unit.