Speedmaster Moonwatch Professional 42 mm, steel on leather strap 310.32.42.50.04.002 Callum it features a dark gunmetal it features a dark gunmetal PVD stainless steel case paired with a striking carbon fiber interface and a grooved black silicone animation ring this self winding mechanical watch provides precision of 2 +2 sec day and a power reserve of approximately 55 hours The watch is driven by the OMEGA Co Axial Master Chronometer Calibre 3861 ) 97 g Calibre Omega 3861 Movement type Manual‑winding Power reserve 50 hours Strap color Black Strap type Leather strap Strap surface Non‑grained calf leather Strap underside Grained calf leather Buckle type Foldover clasp Buckle material Stainless steel