HR Mainspring No. 957 for Vulcain Cricket Wrist Alarm - Steel

HR Mainspring No. 957 for Vulcain Cricket Wrist Alarm, steel. This is the TIME side mainspring, not the Alarm side. See images for precise characteristics. 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 a pretty good job of representing the item.