Comsco Mainspring #1176 for Hampden 18s Factory No. 1696 - Steel

Comsco Mainspring No.1176 for Hampden 18s movements, Factory No. 1696, steel, new in envelope. See image for precise mainspring specifications. Yes, I know the envelope says Hamilton but that's a misprint.  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.