Rolex Factory Mainspring for caliber 700 to 780 movements - Steel

Rolex Factory mainspring for 10½ ligne caliber 700 to 780 movements, steel, new in envelope. Notice Rolex and the logo is stamped on the keeper. These measure at Dennison 6½ x 11 x 12 (metric 1.55 x .10 or just barely under) with a tongue end. The box these were in was labeled Rolex Observatory but the 700 series was used in far more watches than just those marked Observatory. I'll also point out that while these will work fine in a caliber 720 the factory mainspring was 1.55 x .096 so this is just a tiny bit stronger. If you're restoring a Rolex then a purist would want only a factory mainspring.  :)

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 a pretty good job of representing the item.