Doxa · SUB 300

Strap for SUB 300T Sharkhunter / 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
Reference840.10.101.10
FamilySUB 300
MovementETA caliber 2824-2 Hours, Minutes, Seconds | Date
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 300 840.10.101.10

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The SUB 300 840.10.101.10, seen from the bench

The Doxa SUB 300 reference 840.10.101.10 is powered by the automatic ETA 2824-2 calibre with hour, minute, second and date functions. The watch features 20mm lugs and represents the modern evolution of the Swiss brand's dive watch line. The ETA movement ensures reliability and precision for everyday use.

Frequently asked questions

What is the exact lug width of the Doxa SUB 300 840.10.101.10?

The lug width of the Doxa SUB 300 840.10.101.10 is 20 mm. This specific dimension reflects the original Doxa design from the 1960s and requires bespoke compatible straps. You can verify the measurement using a digital calliper, positioned perpendicularly between the two lug pins, excluding any case protrusion.

Which strap is ideal for the Doxa SUB 300 840.10.101.10?

For intensive diving use, we recommend FKM (Viton) rubber or technical fabric NATO: they resist moisture, salt, and UV rays without absorbing marine odours. For hybrid use (water and urban context), vegetable-tanned alligator or calf leather develop natural patina over time and offer tactile elegance. The choice depends on intended use and personal aesthetic preferences.

How do I change the strap on the Doxa SUB 300 840.10.101.10?

Remove the strap using a spring bar tool or dedicated tool: insert the tip into the lateral slot of the lug and lift gently until the pin is released. Extract the pin, then slide the old strap off both lugs. Insert the new strap along both pins, verifying correct positioning before closing with the original spring bar or a deployante buckle.

Are aftermarket straps compatible with the Doxa SUB 300 840.10.101.10?

Yes, provided the lug width is exactly 20 mm. Bespoke straps constructed to this specification ensure perfect fit, wrist stability, and case protection. Avoid adaptations using reducers or spacers, which compromise aesthetics and structural functionality.

How long does a leather strap last on the Doxa SUB 300 840.10.101.10?

A vegetable-tanned leather strap (alligator or calf) typically lasts 3–5 years with regular use and proper maintenance: periodic cleaning with a damp cloth, annual conditioning with natural neutral oil. Extended exposure to salt water accelerates ageing. For frequent diving, alternating with rubber straps extends leather lifespan and preserves natural patina.

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.

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