Cas-Ker Mainspring for Rolex Chronograph caliber 3135 - Alloy

Cas-Ker Mainspring for Rolex Chronograph calibers 3130 to 3135 plus perhaps other as well, likely made by Bestfit, alloy, new in open package. 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.