Omega
Seamaster 120M 2501.51.00— lug 18mm

The Seamaster 120M reference 2501.51.00 is fitted with 18 mm lugs, a specific measurement that characterizes this model. The width is measured between the two case terminals perpendicularly, using a digital caliper. This dimension is essential for selecting compatible straps without adapters.

The material depends on intended use. For maximum versatility, natural alligator (distinct grain texture, dynamic patina) or vegetable-tanned calf leather (softness, moisture absorption) are excellent choices. For intensive marine use, fluorocarbon rubber ensures water grip and minimal maintenance. All materials should be handcrafted with 3.5-4 mm thickness for correct proportions on the 36.25 mm case diameter.

The Seamaster 120M 2501.51.00 uses standard 18 mm spring bars for strap attachment. With the appropriate tool (spring bar tool), remove the spring bar by gently pushing from the open side of the case lug, then extract the old strap. Insert the new strap by aligning the holes with the terminals, then reinsert the spring bar until you hear the click. Avoid hammers; the operation requires calibrated pressure and precision.

Original Omega straps for the 2501.51.00 are built from leather or rubber with strict standards for thickness (3.5-4 mm) and controlled softness. Aftermarket handcrafted straps from specialized manufacturers (like ours) offer selection of noble leathers (genuine alligator, European calf, shell cordovan), customization (length, initials, thread color), and often superior longevity thanks to premium materials and more solid construction. The difference lies in personalization and quality of raw materials, not technical compatibility.

A fine leather strap (alligator, vegetable-tanned calf) worn with care has an average lifespan of 5-7 years if exposed to controlled humidity, up to 3-4 years if frequently in contact with salt water. The patina, visible after 6-12 months, does not represent deterioration but rather natural aging that characterizes genuine leather. Rubber has similar lifespan (5-7 years) but maintains consistent appearance without patina. Storage in a dry place and regular cleaning significantly extend the useful life of any material.