Seiko Prospex SLA041 1975 Recreation Tuna 55th Anniversary Diver

The Seiko Prospex SLA041 1975 Professional Diver’s Re-Creation was released in 2020 as part of Seiko’s 55th Anniversary celebration, paying tribute to one of the most important professional dive watches in the company’s history. The original 1975 Professional Diver’s 600m was developed after Seiko received a letter from a professional saturation diver explaining that existing watches could not withstand the extreme conditions of deep-sea work. The resulting watch became the world’s first diver to use a titanium case and introduced innovations that would influence professional dive-watch design for decades. The SLA041 faithfully recreates that unmistakable “Tuna” architecture with a massive 52.4mm one-piece titanium inner case, protective zirconia ceramic outer shroud, Ever-Brilliant Steel bezel, sapphire crystal, and accordion-style silicone strap. Modern engineering increases its saturation-diving water resistance from the original 600 meters to an extraordinary 1,000 meters, while magnetic resistance is rated to 40,000 A/m. Production was limited to just 1,100 individually numbered pieces worldwide.

Inside is Seiko’s high-grade Caliber 8L35, a 26-jewel automatic movement developed specifically for professional dive watches and assembled at the Shizukuishi Watch Studio. Operating at 28,800 vibrations per hour, it offers manual winding, hacking seconds, a date display, and approximately 50 hours of power reserve. Just as importantly, the SLA041 preserves several engineering concepts pioneered by the 1975 original, including its double-layer construction, monocoque-style inner case and L-shaped gasket designed to resist helium penetration without requiring a conventional helium escape valve. With its enormous shrouded case, professional 1,000-meter rating, historically significant construction and limited 1,100-piece production, the SLA041 is much more than another modern “Tuna”—it is one of Seiko’s most faithful high-end recreations of the groundbreaking watch that established the blueprint for the brand’s extreme professional divers.

Reference: SLA041

Dated: Undated

Limited: 1100 Pieces

Bezel Aligns

Dial: Blue

Bracelet: Blue Silicon Strap

Case Size: 52.4mm x 17.2mm Thickness x 53.5mm Lug to Lug

Lug Width: 22mm

Case Metal: Titanium case with Ever-Brilliant Steel

Movement: Seiko 8L35 - Automatic - Running Spec

Functions: Hours, Minutes, Second, Date

Box and Papers: Box and Papers

Crystal: Sapphire

Bracelet size: 8”

New Unworn Condition

Seiko's history began in 1881 when Kintaro Hattori opened a watch shop in Tokyo. In 1892, he established Seikosha, a factory for producing wall clocks. The company quickly progressed, creating Japan's first wristwatch, the Laurel, in 1913. Despite setbacks like the Great Kanto Earthquake of 1923, Seiko persevered, launching its first watch under the Seiko brand name in 1924.

The post-World War II era saw Seiko's rapid growth and innovation. They introduced Japan's first automatic wristwatch in 1956 and launched the prestigious Grand Seiko line in 1960. Seiko achieved international recognition for accuracy in 1968, winning a Geneva Observatory competition.

The company made a name for its divers in 1965 with the introduction of their first professional dive watch, the 62MAS. This was followed by the iconic 6159-7001 in 1968, which was water-resistant to 300 meters. Seiko gained international recognition in 1975 with the release of the 6159-7010, nicknamed the "Tuna Can" due to its distinctive case shape. In 1969, they revolutionized the industry with the Astron, the world's first quartz wristwatch, ushering a new era of watchmaking that would send waves across the industry through the 70s and 80s. From its humble beginnings to becoming a global watchmaking giant, Seiko's history is characterized by resilience, technological advancement, and a commitment to precision.