HR Quick Fit Mainspring K436 for Felsa 520, 523, Gruen V7 VeriThin - Alloy

HR Quick Fit Mainspring K436 for Felsa caliber 520, 523 & Guren caliber V7 Veri-Thin pocket watch movements plus perhaps many more similar ébauche watches, white alloy, new in envelope. See image for precise mainspring specifications. I likely have several of these so the one you get may differ slightly from the images. I specialize is hard to find watch parts so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.