Seiko SSK001 vs Baltic Aquascaphe GMT

A true GMT on the Miyota 9075: the local hour hand jumps forward and back in one-hour steps without stopping the watch, while the 24-hour hand holds home time. That is the version you want when you land.

200m with sapphire in a 39.5mm case that is 47mm lug-to-lug and 13.8mm thick — a genuine dive watch that happens to have a second time zone, rather than a dress watch with a colored bezel.

Baltic sells direct, so we earn nothing on this link, and it publishes no service price. It also costs substantially more than the Seiko.

Baltic states the Miyota 9075 is a true GMT — the local hour hand jumps independently — which is rare at this level. Add a double-domed sapphire crystal, a sapphire 24-hour bezel, a screwed crown and 200m in a 39.5mm case. Sold direct; we earn nothing on it.

The cheapest mechanical GMT worth owning. The 4R34 hacks and hand-winds, runs 41 hours, and Seiko publishes $176 to overhaul it — the cheapest published mechanical service in the industry.

42.5mm across but only 46mm lug-to-lug and 13.6mm thick, on a 22mm strap. It wears far smaller than the diameter suggests.

It is a caller GMT: the 24-hour hand is what you set, so you adjust it to track a second zone from where you are. Landing in a new zone means resetting the main time the ordinary way. Hardlex rather than sapphire, and 100m with no diver's marking.

The 4R34 is a caller GMT — the 24-hour hand is the one you set, not the local hand — but it is a real mechanical second time zone on a movement whose service price Seiko publishes.