Omega
Seamaster Diver 300M 2133.80.00— lug 20mm

The lug width of the Seamaster Diver 300M 2133.80.00 is 20 millimetres. This measurement is standard for this model and is essential for selecting compatible straps. To measure correctly, position a calliper perpendicular between the two lug shoulders (the ends of the case where the strap is inserted), tracing an imaginary line from shoulder to shoulder. The fitting tolerance is approximately 0.5 millimetres.

For a Seamaster 300M in yellow gold, the most appropriate materials are chocolate brown alligator, which creates a harmonic continuum with the case, or bottle green shell cordovan for those seeking sophisticated contrast. Vegetable-tanned calf leather in cognac tones represents a valid choice for more robust usage contexts. The selection depends on your usage context: if predominantly formal, alligator; if nautical-sporty, calf or rubber; if seeking maximum elegance, high-quality shell cordovan.

Changing the strap on the 2133.80.00 requires a specific tool: a spring bar tool or, alternatively, a small flathead screwdriver. Position the watch on a soft surface. Insert the tool into the slot beneath the lug to release the retaining spring, then extract the lug. Do the same on the other side. Take the new lug compatible with 20 millimetres, insert it gently into the new strap and secure at both ends of the case. If you are not experienced, the Casati Milano atelier can perform the change at their Milan location by appointment.

Yes, any strap with a 20 millimetre lug width is compatible with the Seamaster Diver 300M 2133.80.00. However, we recommend selecting superior quality straps made from precious leathers such as alligator, shell cordovan or vegetable-tanned calf. The artisanal straps online from milanostraps.it are all certified for this lug width and available in various colour and material variants.

The lifespan of a leather strap depends on the quality of the material, the tanning process used and the intensity of use. A high-quality alligator strap with vegetable tanning can last between 5 and 8 years with regular maintenance (gentle cleaning and protection from excessive moisture). Shell cordovan, being denser and more resistant, can reach 10-12 years. It is advisable to avoid prolonged water exposure and, if the 300M is used in actual nautical contexts, alternate with rubber or NATO fabric straps. Straps made by Casati Milano include an 18-month warranty.