Doxa · SUB 300

Strap for SUB 300 Caribbean / Bracelet

Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width20 mm
Case diameter43 mm
Reference821.10.201.10
FamilySUB 300
MovementETA caliber 2824-2 hours, minutes, seconds | date
Year2020
CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the SUB 300 821.10.201.10

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The SUB 300 821.10.201.10, seen from the bench

The Doxa SUB 300 821.10.201.10 is a Swiss diving watch born in 1967, featuring a distinctive orange dial with integrated depth scale. The 42.50 mm stainless steel 316L case houses an ETA Caliber 2824-2 movement with 28,800 A/h beat rate, showing hours, minutes, seconds and date. The 20 mm lug width is essential for correct aftermarket strap compatibility and must be measured precisely between the spring bar or screw attachment points on the case.

Frequently asked questions

What is the lug width of the Doxa SUB 300 821.10.201.10?

The lug width of the Doxa SUB 300 821.10.201.10 is 20 mm. This measurement represents the centre distance between the two attachment points on the case where the strap is inserted. It is essential to verify this measurement with precision before ordering an aftermarket strap, as even a 1 mm difference results in mechanical incompatibility.

Which strap should I pair with the Doxa SUB 300?

The Doxa SUB 300 accepts multiple interpretations: for authentic marine use, FKM rubber in hydrophobic grade is the technical choice without compromise; for sober elegance, natural alligator in grey or burgundy tones enhances the orange dial; for noble ageing, vegetable-tanned calf develops caramel patina over time; for urban versatility, NATO in neutral colours (khaki, grey) maintains technical character without theatricality.

How do I change the strap on the Doxa SUB 300 821.10.201.10?

The Doxa SUB 300 821.10.201.10 uses standard bayonet spring bars for strap attachment. Obtain a steel strap removal tool: position it perpendicular to the wrist, press lightly against the spring until it releases from the anchor hole, then extract the worn strap. Verify that the attachment holes are free from debris before inserting the new strap. The deployante must be affixed to the new strap before installation on the case.

Is the Doxa SUB 300 compatible with generic 20mm aftermarket straps?

Yes, the Doxa SUB 300 821.10.201.10 is compatible with any certified 20 mm quality strap, provided the lateral passants (ears) are dimensioned correctly to enter the case manoeuvre spaces without contacting the crystal or caseback. We recommend straps specifically tested for 42–44 mm models to ensure harmonious proportions and mechanical functionality.

How long does a leather strap last on a diving watch like the Doxa SUB 300?

Leather strap longevity depends on frequency of use and humidity exposure. On a SUB 300 used occasionally in dry environments, quality calf resists 3–5 years before fibre replacement is required. If regularly exposed to marine humidity, even the finest vegetable alligator tends to lose elasticity within 18–24 months. For frequent marine use, FKM rubber offers indefinite durability with only freshwater rinsing maintenance.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

Request an appointment →

Casati Milano · Via XX Settembre 15, Milan · by appointment only