Swartchild Black Shield ALARM Mainspring for Europa 101 & Peter 6000 Alarm Clock

Swartchild Black Shield ALARM Mainspring for Europa 101 and Peter 6000 Alarm Clocks from the 1930's and 1940's (and perhaps beyond), ALARM side spring, new in envelope. Could also very well fit in other alarm and travel clocks as well. See images for precise mainspring specifications. I specialize is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a suitable job of representing the item.