HR Quick Fit Mainspring K557 for AS 1051, Durowe 55, PUW 49, Font 63 - Alloy

HR Quick Fit No. K557 alloy mainspring for AS 1051, Durowe 55, PUW 49, Font 63 caliber movements, new in possibly replacement envelope. See images for precise calibers supported and 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 a satisfactory job of representing the item.