Doxa · SUB 300

Strap for SUB 300 Whitepearl / 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
Reference821.10.011.10
FamilySUB 300
MovementETA caliber 2824-2 hours, minutes, seconds | date
Year2022
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 300 821.10.011.10

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The SUB 300 821.10.011.10, seen from the bench

The Doxa SUB 300 is equipped with the automatic ETA 2824-2 caliber with functions of hours, minutes, seconds and date. The watch features 20mm lugs for the strap. The movement offers the essential complications for a professional diving watch.

Frequently asked questions

What is the exact lug width of the Doxa SUB 300 821.10.011.10?

The lug width of the Doxa SUB 300 821.10.011.10 is precisely 20.00 mm. This measurement must be verified using a digital calliper, positioning the tool perpendicularly between the inner edges of the watch case lugs. It is the critical parameter for selecting a compatible strap without lateral play or mounting resistance.

Which type of strap is most suitable for the Doxa SUB 300 821.10.011.10?

For the SUB 300 821.10.011.10 we recommend vegetable-tanned leather straps for elegant daily wear, cotton-satin NATO or nylon straps for frequent diving, and vulcanised rubber (FKM or esterel) for prolonged humid environments. The choice depends on use: formal (leather), technical-diving (rubber), balanced (NATO).

How do I change the strap on the Doxa SUB 300 821.10.011.10?

Use a spring bar tool to gently lift the lug spring. Position the flat lever under the small metal ball at the end of the spring, then lift until the lug is freed from the case. Repeat on the other end. Insert the lugs of the new strap into the slots and press until the spring clicks. Verify alignment before wearing.

Is an aftermarket strap genuinely compatible with the Doxa SUB 300 821.10.011.10?

Yes, provided the lug width is exactly 20 mm and construction quality is appropriate to the watch's value. An artisanal strap with noble metal fittings, reinforced stitching and naturally tanned leather perfectly complements the SUB 300, amplifying its technical character or elevating its elegance depending on the material chosen.

How long does a natural leather strap last on the Doxa SUB 300 821.10.011.10?

A vegetable-tanned leather strap lasts on average 2-4 years with moderate daily use. Longevity depends on frequency of exposure to water, humidity, perspiration and tanning quality. A vulcanised rubber strap has superior durability (5-8 years), whilst a cotton-satin NATO can last indefinitely if washed periodically.

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