sw 28/9 IWC setting lever spring cal. 8521 8531 8541 / part 854126 61.090.00 = 445

Same part for following calibers : IWC 8521 8531 8541

Setting lever spring Part 85 41 26 (445)

Neuf de stock / New old stock (very minor scratch, not visible on pics, but it looks to be never used)