Marco Mainspring #229 for Waltham Colonial Series Model B 19j & 21j No. 2237 - Steel

Marco Mainspring No. 229 for Waltham Colonial Series (basically a 12s) Model B 19j & 21j movements, Factory No. 2237, steel, new in envelope. See image for further details and precise specifications. 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