Montblanc 4810-503

The Montblanc caliber 4810-503 is a Swiss-made mechanical automatic GMT chronograph movement based on the ETA/Valjoux 7754. It operates at 28,800 vph and features Incabloc shock protection. The caliber number was recently updated to MB 25.03. The GMT complication provides a central hand for tracking a second time zone, which distinguishes it from the similar 7750-based calibers that Montblanc also uses.