Doxa

Professional

Reference Number :

840.10.351.10

Series : SUB 300T

Retail: $1,990

(As of: 05/2025)

This watch is not for sale, this page is just for reference purposes only. If you would like to purchase this watch, please contact Doxa. If you are interested in selling this watch to us, you can contact us here.

Quick TakeStrap on the SUB 300T Professional and you instantly feel connected to a serious piece of dive watch history, but with all the modern chops you need. That bright orange dial isn't just iconic DOXA; it's a beacon of legibility born from actual underwater requirements. This isn't merely a watch that can go deep; it's practically begging for the crushing pressure of 1200 meters, thanks to its robust steel case, screw-down components, and that all-important helium release valve—a nod to the groundbreaking Conquistador of '68. The automatic Swiss movement inside just hums along reliably, needing nothing but your motion to keep going. Using that patented no-decompression bezel feels satisfyingly mechanical, a tangible link to calculating your safety margin. Whether clamped onto your wrist with the supremely comfortable 'Beads of Rice' bracelet or the flexible FKM rubber, complete with that handy wetsuit extension, it feels perfectly balanced and ready for adventure, above or far below the waves. It’s a tool, a legend, and a statement all rolled into one unmistakable package.

DescriptionManufacturing specifications outline the SUB 300T Professional, reference 840.10.351.10, case construction utilizing high-grade 316L stainless steel. This material selection ensures significant resistance to corrosion, a critical factor for marine environments. The case geometry is defined by a diameter of 42.50 mm and a lug-to-lug dimension of 44.50 mm, with a total height profile measuring 13.65 mm. Structural integrity for deep submersion is achieved through a screw-down crown mechanism and a solid stainless steel screw-down case back. These features are integral to the watch's substantial water resistance rating, certified to 120 atmospheres (ATM), which equates to a depth capability of 1,200 meters or 3,937 feet. Protecting the dial is a scratch-resistant sapphire crystal, further enhanced with an anti-reflective coating to maximize legibility by minimizing glare under various lighting conditions, including direct sunlight and underwater scenarios. Incorporated into the case design is a helium release valve (HRV), a feature tracing its lineage back to the original 1968 SUB 300T Conquistador, the first publicly available dive watch with this technology. The HRV is essential for saturation diving, allowing trapped helium molecules to escape the watch case during decompression, preventing potential damage to the crystal or case structure due to internal pressure buildup. The overall architecture pays tribute to its historical predecessor while integrating modern material science and sealing technologies required for contemporary high-performance diving instruments. The case design reflects a purpose-built approach focused on durability and functional performance in extreme underwater pressures.

Powering the timekeeping functions is a Swiss origin mechanical movement characterized by its automatic, self-winding capabilities. This caliber operates at a standard frequency of 28,800 vibrations per hour (4.0 Hz), contributing to the smooth sweep of the seconds hand and overall timekeeping precision. When fully wound, the movement provides a power reserve of approximately 38 hours. As specified, the movement receives decorative finishing applied by DOXA. Time indication is provided through central hour, minute, and second hands, supplemented by a date display complication. User interaction for dive timing is facilitated by a unidirectional rotating bezel, a crucial safety feature preventing accidental reduction of measured dive time. This bezel incorporates DOXA's patented integrated no-decompression dive time calculator, calibrated in feet, allowing divers to monitor dive times in relation to depth without needing external tables. Optimal underwater legibility is paramount; consequently, all elements providing critical dive-relevant information, including bezel markers, dial indices, and hands, are treated with Super-LumiNova® luminescent material. This ensures visibility in low-light or murky underwater conditions. The watch is offered with attachment options including a 316L stainless steel "Beads of Rice" style bracelet or an FKM rubber strap. Both options feature a robust folding clasp mechanism incorporating a ratcheting wetsuit extension system for easy adjustment over dive suits, adorned with the distinctive Doxa fish symbol. The lug width is standardized at 20.00 mm, allowing for strap interchangeability. The dial maintains the brand's iconic aesthetic, presented here in the 'Professional' configuration.

GenderMen

SignaturesDOXA

Country of OriginSwitzerland

Case Size42.5 mm

MovementAutomatic

FunctionsHours, Minutes, Seconds, Date

Power Reserve38 Hours

Case MaterialsStainless Steel

Bezel MaterialsStainless Steel

Lug MaterialsStainless Steel

Case BackSolid

CrownScrew Down