Howard Factory Mainspring for Howard 16s No. 328 - Steel

Genuine Howard Factory Mainspring for Howard 16s 19j to 23j movements, Factory No. 328, steel, new in wrapper. See images for further details. Recently came across a box of original Howard Factory mainsprings, all of them in remarkable condition given their age and considering the thin paper they were wrapped in. Paper stains do not imply a rusty mainspring - I check them carefully. 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.