While almost all traditional systems of length units include a foot-size unit, the choice of smaller units has varied from system to system. Most traditional systems of length units have divided the foot into either 12 or 16 parts. If the division is into 12, an inch-size unit about equal to the length of a thumb results; if it is into 16, a digit-size unit equal to the width of a finger results. This page gives a listing of digit-size units on this wiki.