Hamilton 12s Mainspring No. 1228 Made by Waltham - Steel

Hamilton Mainspring for 12s, Factory No. 1228, marked M.B. (which is supposed to mean Double Brace) made by Waltham, steel, new in frail envelope. See images for further details. These were available in a couple of different strengths and those that I can supply can be found in the drop-down list. This is not the first time I've run across a mainspring that Waltham made for a competing brand. Still it's a nice quality mainspring - and cheap too! I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.