KBK Mainspring #3056 for Ingersoll Reliance 16s Factory No. 2365 - Steel

Kilb - Beck - Kuesel Inc (KBK) Mainspring #3056 for Ingersoll Reliance 16s movements, Factory No. 2365, 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. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.