Unmarked Mainspring for 18s South Bend Factory No. 19528 - Steel

Unmarked Maker Mainspring for 18s South Bend Pocket Watch movements, Factory No. 19528, steel. I suspect this was an early Hammel, Riglander & Co mainspring as it resembles the ones I have from them for Dollar watches. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.