GMT Hand
A watch component, material or construction term describing GMT Hand.
Also known as: 24-hour hand, second-time-zone hand, GMT pointer
Definition
A GMT hand is an additional hand used to display another time reference, usually against a 24-hour scale on the dial or bezel. Because it typically completes one revolution every 24 hours, it also distinguishes day from night in the referenced time zone. Depending on the movement, either the conventional local hour hand or the GMT hand may be independently adjustable; collectors often use 'flyer/traveller GMT' and 'caller/office GMT' to describe those different architectures.
Why it matters
How the GMT hand is adjusted determines how convenient the watch is for actual travel. A 24-hour hand also prevents ambiguity between, for example, 3 a.m. and 3 p.m. in the referenced zone.