Comsco Mainspring #1111 for Hamilton 12s Factory No. 1228 - Steel

Comsco steel mainspring #1111 for Hamilton 12s movements, Factory No. 1228, new in envelope. See images for precise mainspring specifications. The 1288 number on the envelope is a typo. I specialize is hard to find watch parts so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.