Strap for SUB 300T Professional / Bracelet

The lug width for the Doxa SUB 300 840.10.351.10 is 20 mm. This dimension is specific to this model and not interchangeable with the 22 mm lugs found on later-generation Doxa watches. Always verify the exact width between the lug holes using a digital calliper before ordering a replacement strap.

For the SUB 300, straps in dark brown or burgundy alligator are recommended, creating chromatic dialogue with the black dial. Vegetable-tanned Italian calf leather develops noble patina over time and is acceptable for daily wear. For frequent diving use, FKM or EPDM rubber remains stable in salt water. Fabric NATO straps serve as a temporary solution during intensive diving periods.

Position the watch on a dedicated support pad with the dial facing downward. Use a spring bar tool to gently depress the internal spring pin of each lug. Remove the worn strap, then align the new strap ends with the lug holes. Verify that the pin engages with a perceptible double-click when fully seated.

Yes, any strap with a 20 mm lug width is compatible with the SUB 300 840.10.351.10. Artisanal straps featuring vegetable tanning, alligator, or rubber from specialist manufacturers maintain identical attachment specifications. Confirm the strap lacks a keeper loop (passant), as the open lugs of the SUB 300 do not accommodate this structural element.

A quality leather strap (vegetable-tanned calf or alligator) maintains structural integrity for 3-5 years under moderate use conditions, with controlled ambient humidity and seasonal perspiration. Vegetable-tanned leather develops visible patina after 6-12 months. Wear accelerates if exposed to frequent fresh water or prolonged submersion; salt water degrades the material within 2-3 months without protective treatment. Rotating with rubber straps during intensive diving periods is recommended.