Trundle Wheel

A trundle wheel is used to measure distance. It is a wheel attached to a handle so that it rolls along the ground. The wheel is often covered with leather or a rough metal to allow better grip on a surface and ensure it maintains traction. It's of an exact circumference, usually a yard or five feet. Each time it makes a complete rotation it makes an audible click so the user knows they have gone exactly that distance and can count the clicks to determine a longer distance traveled.