Alloy Mainspring for H. Savoie (Lorsa) caliber 236 to 238

Unmarked Swiss Mainspring for H. Savoie (Lorsa) caliber 236, 237, 237BCP, 237BCT, 237BT, 238, 238C movements plus perhaps similar ébauche watches, white alloy. See images for precise mainspring specifications. Yes, I realize someone badly misspelled the name but this is the proper mainspring.  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.