Technical Archive

Doxa
SUB 300 840.10.361.10— lug 20mm

Doxa SUB 300 840.10.361.10: 20mm strap. Alligator, box calf, shell cordovan and rubber, cut and stitched in Milano. Choose your leather.

SUB 300T Divingstar / Bracelet

Artisanal Note

"This model requires a precise 20mm lug width to preserve the original sartorial balance."

Technical Specifications

Doxa 840.10.361.10
Lug Width
20 mm

The essential strap measurement.

Browse 20mm straps →
Reference

840.10.361.10

Movement

ETA caliber 2824-2 Hours, Minutes, Seconds | Date

The Heritage

The Doxa SUB 300 840.10.361.10 is an iconic modern diving watch descended from the legendary SUB line launched in 1959. It features a 42.50 mm stainless steel 316L case, sapphire crystal, unidirectional bezel, and a characteristic orange "Tropical" dial optimized for underwater visibility. The watch is powered by an ETA 2824-2 automatic movement with 25 jewels, 28,800 vph, and date window, offering ±10 seconds/day precision for dives to 300 meters. The 20 mm lug width requires dedicated straps and represents a key specification for this model.

FAQ

What is the lug width of the Doxa SUB 300 840.10.361.10?

The lug width of the Doxa SUB 300 840.10.361.10 is 20.00 mm. This specific dimension requires dedicated watch straps and is not interchangeable with the more common 22 or 24 mm formats. Always measure your lug width before purchasing: place a calliper between the inner attachments of the case, from one side to the other, to verify the exact width.

What is the best strap choice for colour coordination with the Doxa SUB 300?

The orange Tropical dial of the SUB 300 pairs ideally with warm-toned straps: dark brown or cognac alligator, black calf leather, grey pearl shell cordovan. For professional diving, opt for FKM rubber in dark grey or black, which resists saltwater and chlorine exposure. Avoid bright red or orange straps, which would create discordant contrast with the dial.

How do I change the strap on the Doxa SUB 300 840.10.361.10?

Strap replacement requires a spring bar tool (specialized removal device). Locate the metal springs at the ends of the lugs and gently press one spring downward with the tool, then extract the bar from its hole. Repeat on the other side. Insert the bar into the new strap, aligning the holes, then reposition the spring. Verify that both sides are securely fastened. Professional installation is available through Milano Straps or the Casati Milano atelier.

Can I use an aftermarket strap compatible with the Doxa SUB 300?

Yes, any strap with a 20 mm lug width is technically compatible. However, we recommend selecting artisanal straps of high quality, made with noble materials (alligator, vegetable-tanned calf, vulcanised FKM rubber). Milano Straps offers a curated selection of 20 mm straps that guarantee durability and aesthetic coherence with the toolwatch character of the SUB 300.

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

Leather strap durability depends on usage and maintenance habits. A high-quality leather with vegetable tanning, subjected to ordinary wear (5–8 hours daily), maintains structural integrity for 3–5 years. Constant humidity exposure shortens this lifespan to 12–24 months. To extend strap life, apply protective balm every six months, avoid prolonged immersion with leather straps, and consider FKM rubber for humid environments. Milano Straps straps are constructed for longevity: premium leathers and artisanal techniques reduce the risk of premature failure.