Swartchild Black Shield Clock Mainspring 3.00 x .23 mm x 14¼" Junghans 79

Swartchild & Co Clock Mainspring, OPEN LOOP End, Dennison 1/8 x .009 x 14¼, from the 1950's, steel, made in France. Suitable for H.A.U. 79, Junghans 79. See images for precise mainspring characteristics. The stain on the envelope is leftover tape sticky-goo. 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