Few watch brands can claim to have changed the course of horology twice, but Seiko is one of them. Founded in Tokyo in 1881, the manufacture introduced the world's first quartz wristwatch in 1969 — the original Astron — and then rewrote the rules again in 2012 by launching the world's first GPS Solar watch under the same name. The Astron collection sits at the top of Seiko's range and represents the brand's most advanced thinking in timekeeping technology: a line built for the modern world traveller who demands absolute accuracy without ever touching a crown.

Reference SSE109J1 is a 44.8 mm GPS Solar world time watch in titanium with a super-hard coating, combining serious technological credentials with a well-executed and wearable case. At just 12.4 mm in thickness, it wears notably lighter and slimmer than its diameter might suggest — a direct benefit of the titanium construction and the compact Calibre 8X22 movement within. The blue dial is nicely structured, with applied baton hour markers and hands coated in Seiko's LumiBrite for strong legibility in low light. A world time ring around the inner bezel tracks 40 time zones at a glance, and a date display completes the layout. At its heart beats the Seiko Calibre 8X22, a GPS Solar movement that synchronises with GPS satellites at the touch of a button, automatically adjusting to the correct local time zone anywhere on Earth. Accuracy is rated at ±15 seconds per month without a GPS signal. The sapphire crystal carries Seiko's proprietary super-clear anti-reflective coating. The bezel is crafted in black ceramic, engraved with world city references. Water resistance is rated to 100 metres. The watch is fitted on a titanium bracelet with a three-fold clasp with push-button release.

This Seiko Astron GPS Solar is in good used condition and comes in a Grand Seiko travel box. The bracelet will fit a wrist up to 18cm. 3 months warranty!