PM Merelloy Mainspring #222 for 21/0s Hamilton No. 2921 - Alloy

PM Merelloy Mainspring #222 for 21/0s Hamilton, Factory No. 2921, alloy, new in envelope. See images for further details. I likely have several of these so the one you get may differ slightly 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.