Waltham Factory Mainspring for 16s Model 1862 Factory No. 2208B - Steel

Waltham Mainspring for 16s Model 1862 movements, Factory No. 2208B, steel, new in a very frail envelope. See images for further details. As you can imagine, this mainspring has likely been on the shelf for quite a few years (probably over 100) but I inspect all these steel mainsprings carefully before I list them, and I guarantee them unconditionally even given the age. Images do a pretty good job of representing the item.