Newall SUPER Security Mainspring #615 for Hamilton 12s No. 1228 / 3028 / 718071 - Alloy

Newall SUPER Security Mainspring No. 615 for Hamilton 12s movements, Factory No. 1228 / 3028 / 718071, alloy, new in envelope. See images for precise mainspring specifications. 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.