Watches were also mounted on a short leather strap or fob, when a long chain would have been cumbersome or likely to catch on things. This fob could also provide a protective flap over their face and crystal. Women's watches were normally of this form, with a watch fob that was more decorative than protective. Many keywind watch movements make use of a fusee, to improve isochronism. The fusee consist of a fine chain attached to the mainspring barrel at one end, and a special cut conical pulley at the other end. When the spring is fully wound(and its torque the highest), the full length of the chain will be wrapped around the pulley, causing the force of the mainspring to be exerted on the smallest diameter portion of the pulley.
