Watch Glossary

Measurement of how accurately a chronometer maintains timekeeping over extended periods

Standard of accuracy required for movements to be officially certified as chronometer-quality

GMT-Master II with red and black bezel insert, resembling Coca-Cola branding.

Specialized dial for commercial diving watch, often with unique printing or design.

Balance wheel designed to maintain accurate rate despite temperature fluctuations

Historical device used to adjust effective hairspring length for rate regulation

Historical watch model series emphasizing robust construction