Newall SUPER Security Mainspring #901 for South Bend 18s No. 19528 - Alloy

Newall SUPER Security Mainspring #901 for South Bend 18s, Factory No. 19528, alloy, new in envelope. See images for further details and precise mainspring specifications. I likely have several of these so the one you get may differ slightly from the images. I specialize is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item