FITRITE Clock Mainspring 5.70 x .25 mm x 820 for 8-Day Travel / Alarm

FITRITE Clock Mainspring, OPEN LOOP End, Dennison 38 x 0 x 32", for unspecified maker 8-day Travel / Alarm clocks made from the 1950's or later, steel. See images for further details. Someone prior to me noted that these are the same as a Bestfit L570/1. Was originally sold as part of assortment No. 2880 for clockmakers. 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.