USR Mainspring for E. Howard 6s "G" Movements No. 242 - Steel

USR Mainspring for E. Howard (old Howard) 6s or "G" movements, factory No. 242, steel, new in distressed envelope. USR is short for Ulysse Sandoz-Robert of La Chaux-de-Fonds, Switzerland. Dennison 11 x 7 x 17, see image for further details. 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.