Zenith
Chronomaster Open
Ref. 03.3300.3604/21.M3300
The Zenith Chronomaster Open (reference 03.3300.3604/21.M3300) is a high-end chronograph featuring the iconic Zenith El Primero automatic movement, known for its precision and 36,000 vibrations per hour. This model stands out with an open case back showcasing the movement, a bold black matte dial with tricolored chronograph subdials, and a stainless steel bracelet. It is part of the Chronomaster collection, renowned for its chronometric accuracy and heritage dating back to 1969.
crystalSapphire, scratch-resistant, exhibition case back
braceletStainless steel, folding clasp, 45.5mm lug-to-lug width
movementZenith El Primero automatic (Caliber 3604, 36,000 vph, 60-hour power reserve, 35 jewels)
functionsOne-tenth second chronograph (central hand), 60-minute and 60-second counters, small seconds at 9 o'clock
lug width45.5
dial colorBlack matte with luminous baton hour markers and tricolored chronograph subdials (60-minute, 60-second, and running seconds)
case diameter39.5
case materialStainless steel
water resistance100
year2025
A registered Zenith 03.3300.3604/21.M3300 carries a permanent RGATT passport: origin, history and owners, verifiable by anyone, and a documented history makes a watch easier to sell.