Strap for SUB 300T Sharkhunter

The Doxa SUB 300 840.10.101.20 features a lug width of 20 millimetres. This measurement, taken from the inner shoulder to the opposite inner shoulder, is the standard specification across the entire SUB 300 family and has been engineered to maintain optimal proportions between case and wrist. Any compatible strap must strictly respect this dimension to ensure proper fit without play.

The choice depends on intended usage. For daily elegance, we recommend a vegetable-tanned calf leather strap that develops golden patina over time, creating striking contrast with the orange dial. For frequent diving, FKM (Viton) rubber offers complete resistance to saltwater and chlorine. Alligator leather in dark brown maintains inherent lustre, whilst NATO straps in Cordura nylon provide practicality and robustness in genuine marine environments.

To change the strap, you will need a specialist tool called a spring bar tool. Position the bifurcated end of the tool against the pin securing the strap to the case, apply gentle downward pressure to compress the internal spring, and pull the strap outward. Repeat on the opposite side. Insert the new strap by aligning the lugs with the case shoulders and re-insert the pins. Verify that the strap is securely fastened before wearing the watch.

Yes, absolutely. It is essential that the aftermarket strap is manufactured for exactly 20-millimetre lug width. Many superior quality straps such as alligator, shell cordovan or vegetable-tanned leather are produced exclusively by specialist craftsmen specifically for this lug specification. Always verify that the manufacturer specifies 20 mm; using lugs of different widths compromises both aesthetics and wearing security.

Longevity depends on the tanning method and environment of use. A vegetable-tanned strap typically lasts 18–24 months if exposed to frequent marine humidity; in dry environments, it easily reaches 3–4 years. Alligator and shell cordovan are more resistant to moisture and achieve 2–3 years even with regular diving. If your SUB 300 is used primarily in swimming pools or the sea, we recommend alternating leather straps with nylon NATO or Viton rubber to extend the lifespan of the leather accessory.