Paulson Mainspring No. 57M for Aurore caliber 16T, A. Michel caliber 65, 66 - Steel

Paulson Mainspring No. 57M for Aurore caliber 16T, A. Michel caliber 65, 66 movements and perhaps others, steel, new in envelope. See images for precise mainspring specifications. I specialize in 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.