Arnold & Son Watch Nebula 40 Steel 1NEGS.B03A.C169S. Arnold & Son has reworked its Nebula collection, giving it a more striking case with a universal diameter of 40 mm while retaining its remarkably finished movement and unique abundance of watchmaking tradition. The aesthetics of the Nebula collection are unlike any other skeleton: its structure conveys watchmaking spirit, its style expresses unique elegance, and the overall effect is one of outstanding fin