Seagull 6139HK Skeleton Automatic Watch — ST2502K, 44mm, Black Case, Red Accents

Seagull 6139HK Skeleton Automatic Watch — ST2502K, 44mm, Black Case, Red Accents

The Seagull 6139HK is a 44mm in-house ST2502K automatic skeleton watch — an open-work dial revealing the gear train and balance assembly through a racing-inspired black and red design. Black-coated 316L stainless steel case at 12mm, sapphire crystal, nylon strap with red contrast stitching, 50m water resistance. Two variants: 814.52.6139HK and 814.22.6139HK.

Key Specifications

Variants

814.52.6139HK: Confirm specific dial and accent combination from the product listing image. 814.22.6139HK: Confirm specific dial and accent combination from the product listing image.

Both variants share the black case, red accent design language and ST2502K movement — the suffix numbers indicate configuration differences in strap or accent treatment.

Seagull ST2502K In-House Movement

The ST2502K is a Seagull in-house automatic caliber — different from the ST17 (Natural Series Polaris), ST21 (816.423 multifunction) and ST25 (M160S Flywheel) found on other Seagull pages at Jewelry Addicts. At 25 jewels and 21,600 vph with a 40-hour power reserve, the ST2502K is a standard-specification sport automatic. The “K” suffix in the Seagull caliber designation typically indicates a modified or variant version of the base ST25 caliber.

The movement is fully visible through the skeleton dial from the front — the gear train bridges, balance wheel oscillation and the decorative movement architecture are on display during wear.

Skeleton Dial

The open-work dial exposes the ST2502K movement beneath the dial layer — bridges and structural elements frame the visible mechanics rather than enclosing them behind a solid dial surface. The balance wheel oscillates at 21,600 vph (6 beats per second), visible as a continuous rocking motion at the 6 o’clock position.

The multi-layer structure creates depth: the outer chapter ring and hands sit above the open-work structure, which sits above the movement components below. Red accent elements thread through the skeleton architecture — matching the nylon strap’s contrast stitching to create a cohesive design palette.

Black and Red Racing Aesthetic

The 6139HK’s colour scheme — black DLC case, red accents throughout the dial, red stitching on the nylon strap — creates a motorsport-inspired character. The “6139” model designation references the era of 1960s–70s racing chronographs in watch culture; applied here to a skeleton watch with the same visual energy without the chronograph mechanism.

The nylon strap is lightweight, flexible and appropriate for the sport character — a leather or steel bracelet would shift the watch toward dress territory inconsistent with the racing dial design.

44mm Case

At 44mm the 6139HK is the largest case in the Seagull branded range at Jewelry Addicts. The 12mm thickness is moderate for a 44mm automatic. Appropriate for wrists above approximately 17cm for balanced proportions.

Seagull 6139HK in the Range

The 6139HK occupies the sport/skeleton position in the Seagull range — distinct from the dress watch territory of the 816.423 (moonphase), Polaris (wave dial) and M160S (open-heart formal):

The 6139HK is the only Seagull at Jewelry Addicts in a sport/skeleton format with a black coated case.

Who Is the Seagull 6139HK For?

The 6139HK is built for:

• Sport skeleton buyers who want the Seagull in-house caliber in an open-work racing design at 44mm
• Black and red colour combination buyers who want the aggressive motorsport palette on an in-house automatic
• Seagull brand buyers who want the manufacturer’s own skeleton caliber rather than a generic movement in a skeleton case
• Buyers who want the largest available Seagull case size (44mm) in the sport automatic format

How It Compares

vs. Seagull M160S Flywheel Legend — M160S uses ST25 at 39mm with open-heart formal character on steel bracelet. The 6139HK uses ST2502K at 44mm with full skeleton sport character on nylon. Both in-house Seagull automatics — completely different aesthetics and wrist positions.

vs. Bonest Gatti BG9902 Ghost Speed — BG9902 uses Citizen automatic at 40mm in steel tonneau with turbine skeleton and IP68. The 6139HK uses Seagull ST2502K at 44mm in black steel with red accents on nylon. Both sport skeleton automatics — choose BG9902 for Citizen movement and IP68; choose 6139HK for Seagull in-house and the 44mm black/red racing character.

vs. OUPINKE 3268 Globe Skeleton — OUPINKE uses Seiko automatic at 42mm with globe seconds display on tungsten steel. The 6139HK uses Seagull ST2502K in black DLC with skeleton racing dial. Different skeleton approaches — globe seconds vs full open-work.

More from Jewelry Addicts

• Seagull Watches at Jewelry Addicts — full Seagull range
• Seagull 816.423 Moonphase — most complicated Seagull in the range
• Seagull M160S Flywheel Legend — open-heart dress Seagull alternative
• Bonest Gatti BG9902 Ghost Speed — sport skeleton alternative
• Best Automatic Watches Under $500 — full roundup