Newall SUPER Security Mainspring #529 for Waltham 12s Colonial No. 2237 - Alloy

Newall SUPER Security Mainspring #529 for Waltham 12s Colonial B Movements, Factory No. 2237 (& 2269), alloy, new in envelope. See image for specifications and further details. I likely have several of these so the one you get may differ slightly from the images. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.