Tru-Power Mainspring BU10B for AS 1673, 1674 automatic - Alloy

Tru-Power Mainspring with attached bridle BU10B for AS caliber 1673, 1674 automatic movements and perhaps others as well, alloy, new in envelope.   See images for precise mainspring specifications. 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 so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.