Newall Security Mainspring #624 for Hamilton 6/0s Factory No. 2321 - Steel

Newall Security Mainspring #624 for Hamilton 6/0s, Factory No. 2321, steel, new in envelope. See images for further details. Someone may have marked that they are 2521 but the reality is that the specs for the 2321 and 2521 are so close it's silly for them to be different. I likely have several of these so the one you get may differ slight from the images. 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