HR Mainspring SA355 for Howard 12s Factory No. 553 - Alloy

HR Mainspring SA355 for Howard 12s movements, Factory No. 553, alloy, new in envelope. See images for precise mainspring specification. 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.