Elgin Factory Mainspring for 12s Grade 657 (LIP R40) Pocket Watch movement - Alloy

Elgin Factory Mainspring for 12s Grade 657 movement, alloy, new in open envelope. This Grade 657 is a LIP caliber R40 based Swiss pocket watch movement. See images for further details. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item