Comsco Mainspring #1110 for Hamilton 12s Factory No. 3028 - Steel

Comsco Mainspring #1110 for Hamilton 12s Movements, Factory No. 3028, steel, new in envelope. Distributed by Burton M. Reid and Sons. See image for specifications and further details. Not a particularly common mainspring. 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.