Benrus Travel Clock Alarm Mainspring #723 made by FITRITE

FITRITE Mainspring for Benrus Travel Clock Alarm, #723, from the 1930's and 1940's (and perhaps beyond). Could also very well fit in other clocks and perhaps even some watches. See image for precise mainspring characteristics. I specialize is hard to find watch & clock parts and all parts are unconditionally guaranteed. Images do a pretty good job of representing the item.