Hamilton Model 23 Navigators Chronograph Alloy Mainspring No. 37644

Hamilton Mainspring for 16s Model 23 Navigators Chronograph, alloy, new in envelope. Come across one of these every 2 years or so, eventually they will be impossible to find. I specialize is hard to find watch & clock parts and all parts are unconditionally guaranteed. Images do a pretty good job of representing the item