SEA-GULL D819 Open-Heart Watch – ST2502 Movement, Day-Date, Roman Numerals, 42mm

SEA-GULL D819 Open-Heart Watch – ST2502 Movement, Day-Date, Roman Numerals, 42mm

The SEA-GULL D819 is a formal dress watch built around the genuine Seagull ST2502 automatic movement — a well-documented Chinese-manufactured caliber with a distinctive three-window layout: a day-of-week display at 9 o’clock, a date display at 3 o’clock, and an open-heart window at 6 o’clock showing the balance wheel in motion. White textured Roman numeral dial with blue hands. Stainless steel case with transparent exhibition case back. Black crocodile-texture leather strap. 42mm diameter, 13mm thick, 50m water resistance.

Key Specifications

Seagull ST2502 — Genuine Open-Heart Movement

The ST2502 is a real, well-established automatic movement manufactured by Tianjin Seagull, first released around 2000 and produced continuously since. It’s specifically engineered as an “open heart” caliber, with the balance wheel positioned to be visible through a dial cutout — a design lineage Seagull itself describes as inspired by the open-heart tradition seen in watches from established Swiss houses like Vacheron Constantin.

The standard ST2502 layout matches the D819 exactly: hour, minute, and seconds hands at the centre, a date hand at 3 o’clock, a day-of-week hand at 9 o’clock, and the visible balance wheel at 6 o’clock. Running at 21,600 vibrations per hour with a power reserve in the 42-45 hour range, it’s a genuinely capable multifunction automatic — not a generic unnamed movement.

Day and Date Display

The dial’s two sub-windows give genuine daily-use functionality: the 9 o’clock position shows the day of the week, while the 3 o’clock position shows the date on a 1-31 scale. Both are driven directly by the ST2502 movement rather than being decorative.

Roman Numeral Dial with Blue Hands

The white textured dial uses Roman numeral hour markers with a fine dotted minute track around the edge — a classic dress watch layout. Blue hour, minute, and sub-dial hands provide clear contrast against the white face, a detail commonly associated with formal mechanical watch design.

Transparent Case Back

In addition to the open-heart window on the dial face, the rear case back is also a transparent exhibition window, showing the automatic rotor and the rest of the ST2502 movement architecture from behind.

Stainless Steel Case and Leather Strap

The case uses a polished silver-tone stainless steel finish in a classic round shape. The crown has a ridged, threaded texture for an easier grip when setting the time and adjusting the day/date functions. The strap is black with a crocodile-texture pattern and a silver-tone buckle.

50m Water Resistance

Rated for daily life water resistance — suitable for handwashing and rain only. Not suitable for bathing, showering, swimming, diving, or hot water exposure. Keep the watch away from steam and prolonged water contact.

Style Variants

Available in D819.622, D819.624, D819.625, and D819.626, with options for the watch head alone or paired with the matching strap.

Care Notes

Keep the watch away from hot water, steam, and prolonged water exposure. Wipe the leather strap and case with a soft, dry cloth after wearing for routine maintenance.

FAQ

What movement does the D819 use? The Seagull ST2502 — a genuine automatic movement from Tianjin Seagull, first released around 2000, specifically designed as an open-heart caliber with a visible balance wheel. It runs at 21,600 vph with a power reserve of approximately 42-45 hours, and includes day and date complications.

Is the visible balance wheel a tourbillon? No. It’s an open-heart display — the balance wheel oscillates in a fixed position, visible through the dial cutout. A tourbillon is a distinct, more complex complication where the entire escapement rotates within a cage; that mechanism is not present in the ST2502.

Is it waterproof for swimming? No — rated for daily life water resistance only (handwashing and rain). Not suitable for swimming, showering, bathing, diving, or hot water exposure.

What do the two sub-dials show? The 9 o’clock window shows the day of the week; the 3 o’clock window shows the date on a 1-31 scale.

Can I see the movement from the back? Yes — the case back is a transparent exhibition window showing the automatic rotor and movement.

What size is the watch? 42mm diameter, 13mm thick — a classic dress watch proportion.

Fashion business mechanical watch

self winding mens watch

Watch size

Dial Diameter: 42mm
Case Thickness: 13mm
Watch Length: 210mm
Belt Width: 20mm
Water Resistance: 50 M

Independent window design

3-point independent calendar window
6-point independent hollow perspective
9-point independent week window

High quality hardware accessories

Thread crown

50 meters life waterproof

This watch can be used for hand washing and rain.You can’t take a bath, take a bath, swim, etc.

Transparent back cover

Seagull movement ST2502

High swing frequency,low error,stable travel time,high efficiency power storage

Scenario shows

Environmentally friendly packaging gift box

List of items:
Seagull watch box * 1
Watch manual * 1
warranty card * 1