Seagull M160S Flywheel Legend Automatic Watch — ST25, Open Heart, Day-Date, 39mm

Seagull M160S Flywheel Legend Automatic Watch — ST25, Open Heart, Day-Date, 39mm

The Seagull M160S is a 39mm in-house ST25 automatic dress watch from Seagull’s Flywheel Legend collection — an open-heart aperture at 6 o’clock revealing the balance assembly, day-of-week display at 9 o’clock, pointer date at 3 o’clock, guilloché-textured silver dial with blued hands, sapphire crystal, polished 316L stainless steel case at 13mm and integrated steel bracelet with folding clasp. 3ATM water resistance.

Three models available on this page: M160S (this specification), M162S and M163S. Each model has different dial and complication configurations — confirm the specific model when ordering.

Key Specifications — M160S

Seagull — Manufacturer Background

Seagull Watch Group (Tianjin Sea-Gull Watch Group Co.) is China’s largest watch manufacturer and one of the most significant mechanical movement producers globally. Founded in Tianjin in 1955, Seagull manufactures its own movements in-house — a distinction shared with very few watch manufacturers at any price globally. The ST25, the movement in the M160S, is manufactured entirely at Tianjin by Seagull’s own engineers and technicians.

The M160S is a Seagull-branded watch — manufactured and sold under the Seagull name rather than as an OEM movement supplied to another brand. Buying the M160S means buying directly from the movement manufacturer.

Seagull ST25 In-House Movement

The ST25 is an in-house Seagull automatic caliber — 25 jewels, 21,600 vph, automatic self-winding with manual winding supplement. The movement drives the day indicator and pointer date complications in addition to standard hours and minutes display.

In-house significance: Most watches in the under-$500 category use movements purchased from Seiko (NH35), Miyota or other movement manufacturers. The Seagull M160S uses a movement Seagull designed and builds itself — a different proposition from an assembler brand using bought-in calibers.

The exhibition caseback presents the ST25 movement in operation — automatic rotor, gear train and balance wheel visible from the rear.

Open-Heart Balance Display

The open-heart aperture at 6 o’clock reveals the balance wheel oscillating within the movement. The balance wheel is the timekeeping element — it oscillates at 21,600 vph (6 beats per second), and the escapement releases the gear train one tooth at a time with each oscillation.

This is not a tourbillon. A tourbillon is a specific complication where the escapement and balance wheel rotate in a cage to counteract the effects of gravity on positional accuracy. The M160S open-heart display shows the balance wheel and escapement in their fixed position — a standard configuration that is visible because of the dial aperture. The visual effect of seeing the balance wheel oscillate is the same in both cases, but the mechanism is entirely different. Tourbillons cost significantly more to produce and the M160S does not contain one.

The open-heart provides the visual engagement of watching a mechanical movement operate without requiring a tourbillon mechanism.

Day Indicator and Pointer Date

Day indicator at 9 o’clock: Shows the current day of the week (Monday through Sunday) via a sub-dial with a central hand pointing to the abbreviated day name.

Pointer date at 3 o’clock: A hand sweeps an arc of date numerals (1–31) pointing to the current date — a “pointer date” or “wandering date” display. The pointer date is more visually distinctive than a standard date window and is specifically associated with vintage European dress watch design.

The combination of day indicator and pointer date with the open-heart balance display creates a multi-layered dial that provides more information and visual interest than a standard three-hand design.

Guilloché Dial

The textured silver dial uses a guilloché-style radial or geometric pattern — creating directional light interaction that shifts as the wrist moves. The blued hands contrast against the silver field, creating the colour combination of 19th and early 20th century formal dress watch design.

3ATM Water Resistance

30m — splash and rain protection. Not suitable for swimming, handwashing or submersion. Standard for an in-house dress watch from a traditional manufacturer where the focus is movement architecture rather than dive specifications.

Who Is the Seagull M160S For?

The M160S is built for:

• In-house movement buyers who specifically want a watch designed and manufactured by the movement maker — not an assembler brand using NH35 or Miyota
• Open-heart balance display buyers who want the visible mechanical operation without the misrepresentation of “tourbillon” marketing
• Pointer date buyers who want the wandering date display on an in-house automatic
• Seagull brand buyers who want the manufacturer’s own product rather than a third-party brand using Seagull movements

How It Compares

vs. Seagull ST2557 Automatic — Another Seagull-branded in-house movement watch at 1,344 impressions. Check that page for the ST2557 complication and dial specification to compare within the Seagull branded range.

vs. OLEVS 9910 Open Heart — The OLEVS uses a generic automatic with open-heart at a lower price. The M160S uses Seagull’s own ST25 in-house movement with day and pointer date complications — different movement provenance and significantly more dial information.

vs. Farasute 5506A Dual-Eye — The Farasute uses Hangzhou automatic at 40mm with dual-eye display. The M160S uses Seagull ST25 at 39mm with open-heart and day/pointer date — in-house movement vs Chinese custom, different complications.

More from Jewelry Addicts

• Seagull Watches at Jewelry Addicts — full Seagull brand range
• Seagull ST2557 Automatic — related Seagull in-house movement watch
• Farasute NL-007M Full Calendar — Seagull automatic full calendar alternative
• Best Automatic Watches Under $500 — full roundup