What is a CHRONOMETER? Test vs COSC certificate - positions, service, amplitude, timegrapher...

I'm an accuracy freak, I set my watches to the second, I can't stand a watch that runs erratically, and I want to know if I made a good purchase and if my watches are healthy or need a service. Today I test a 30+ year-old Zenith Chronometer-grade watch that has gone through one service 3 years ago. Let's see if it still matches COSC standards!!!

• #entertainment
• #rolex
• #patek
• #hodinkee
• #watch
• #watches
• #collection
• #mr_beast
• #revolution
• #accuracy
• #test
• #cosc
• #chronometer
• #chronograph
• #time
• #learn
• #lesson
• #timegrapher
• #zenith