H. & W. Perrin Co. Mainspring for AS 552, 562, Felsa 250, 253, 264, 265 - Steel

H. & W. Perrin Co Mainspring for AS caliber 552, 562 & Felsa caliber 250, 253, 257, 264, 265 movements and perhaps others as well, steel, 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. H. & W. Perrin is the largest supplier of horological materials in Canada. Images do an adequate job of representing the item.