Montblanc
Heritage Small Second
Ref. mod578
The Montblanc mod578 (or mod578 series) is a hand-wound mechanical watch featuring the MB 23.03 movement, based on the Unitas/ETA 6498 caliber. It combines vintage-inspired design with modern complications like a world time indicator and 24-hour display, making it a notable piece for watch enthusiasts. The watch is part of Montblanc’s heritage collection, often using revamped historical movements.
crystalsapphire (domed)
braceletleather strap with carbon fiber texture (e.g., e-strap for smartwatch variants) or stainless steel bracelet (not explicitly confirmed for mod578 but implied in other models)
movementMB 23.03 (based on ETA/Unitas 6498), hand-wound, 17 jewels, 46-hour power reserve, 21,600 vph (3Hz), Incabloc shock absorption, COSC-certified
functionsworld time indicator, 24-hour display, off-center seconds, date (in some variants), adjustable in both directions, anti-shock protection for date adjustment (8 PM–12 AM)
dial colorblack (or blue for some variants) with salmon-colored dial in limited editions
case diameter44 mm (or 40 mm for limited editions like the Small Second 38)
case materialstainless steel
water resistance30 meters
year2000s
A registered Montblanc mod578 carries a permanent RGATT passport: origin, history and owners, verifiable by anyone, and a documented history makes a watch easier to sell.