Strap for SUB 300 Professional / Bracelet

The Doxa SUB 300 821.10.351.10 is equipped with a 20mm lug width, a specific dimension for this model that reflects professional diving watch proportioning standards. Correct measurement is performed with a metal ruler, positioning the reference orthogonal to the lugs and calculating the internal centre-to-centre distance. This precision is mandatory before purchasing any aftermarket strap.

The best strap choice depends on intended use. For technical diving and saltwater environments, FKM (Viton) rubber is supreme: total chemical resistance, zero deterioration, optimal grip with wet diving suit. For daily wear with occasional water exposure, immersion-grade alligator (vegetable tanning) develops a tobacco patina that emphasises the watch's instrumental aesthetic and orange dial. NATO straps in mil-spec polyamide offer versatile aesthetics and zero maintenance. All options are compatible with the 20mm lug width.

Strap replacement requires a spring bar removal tool to disengage elastic pins from the lug eyelets. Position the watch on a soft surface (microfibre cloth), then insert the flat tip of the tool into the lower opening of the first lug, apply gentle pressure to retract the internal spring and free the pin. Repeat for the opposite lug. The operation takes 3-5 minutes. Those without a dedicated tool should entrust the task to a specialised service centre to avoid scratching the case.

Yes, any strap with a 20mm lug width is compatible with the 821.10.351.10. However, it is essential to verify the measurement before purchase: 18mm or 22mm straps will not install without damaging the lug eyelets. Specialist strap suppliers offer selections dedicated to this lug width, with options in leather, NATO, and rubber. Always verify technical specifications and compatible pin dimensions (typically 1.5mm diameter).

Leather strap durability depends on material and use environment. Immersion-grade alligator with vegetable tanning guarantees 4-5 years of frequent use in marine environments with proper maintenance (rinsing and drying after immersion, seasonal conditioning with natural oils). Traditional calf leather has similar durability if protected from direct saltwater exposure. Shell cordovan, being denser, reaches 6-7 years. To extend strap life, avoid prolonged saltwater immersion without subsequent freshwater rinsing. FKM rubber straps exceed 8-10 years without appreciable deterioration, making them the technical option for intensive underwater use.