Newall SUPER Security Mainspring #904 for South Bend 12s No. #55528 - Alloy

Newall SUPER Security Mainspring #904 for South Bend 12s, No. 55528, T-end, alloy, new in dirty envelope. See image 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