APNivaflex automatic mainsprings for wristwatchesNivaflex mainsprings from Boley for automatic winders. Products namewidthØthicknesslengthcalibreitem No.1971x0.639.00.10340AP 2120/21820197101989x0.679.00.08450AP 2124/29820198902049x0.709.00.094400AP 2123820204902124x0.788.00.077390AP 214082021240