Marco Marshalloy Mainspring 2721M for ETA 500, 501, 505, 508, 545, Gruen 354 - Alloy

Marco Marshalloy Mainspring 2721M for ETA 500, 501, 505, 508, 545, Gruen 354 caliber movements plus perhaps similar ébauche watches, white alloy, new in envelope. See images for precise mainspring specifications. 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.