Watch Glossary

GMT-Master II with black and blue bezel insert, resembling Batman's color palette.

Auction house observation of competitive escalation causing buyers to exceed pre-sale estimates.

Balance wheel made of two different metals to automatically compensate for temperature changes

Auction term for providing minimal provenance documentation on vintage pieces to reduce liability.

Hairspring with specially shaped terminal curve invented by Abraham-Louis Breguet for improved chronometry

Verification process confirming genuine Crown military issuance by examining hallmark placement and stamps.

Case back stamped with broad arrow symbol denoting British or Commonwealth military issue.

Standardized position on case back or lug area where broad arrow stamp is applied.

Method of verifying military Crown ownership mark positioning and depth on case crown.

British military property mark denoting Crown ownership; stamped on case back or dial of service watches.

Authentication marker establishing military issuance history through official Crown ownership symbols.

Historical records and certificates authenticating military issue and ownership history.

Analysis of Crown mark surface characteristics determining military issue legitimacy.