Convert from arms-length to digit

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 (digit)
The digit is a historic unit of distance equal to the width of a person's finger. Used in all the ancient civilizations of the Middle East and Mediterranean, the digit was equal to 0.75 inch or 19 millimeters with only the smallest variations. Typically, there were 4 digits in a palm, 16 in a foot, and 24 (sometimes 28) in a cubit. The word digit is from the Latin word for a finger or toe, digitus.