Omega
Seamaster 120M 2311.21.00— lug 20mm

The lug width is 20mm, which is the distance between the case lugs that hold the strap at 20 millimetres. This width is standard on this model and is the essential parameter to identify compatible straps online.

For a bimetallic yellow gold and steel case, an alligator in dark shades (black, brown, burgundy) emphasizes the robustness without competing with the gold. Alternatively, a vegetable-tanned calf creates elegant pairings and ages magnificently. For summer, shell cordovan offers natural rigidity without the weight of rubber.

Remove the original strap by identifying the two pins that hold it to the case. Use a tool called a spring bar removal tool (available online) to push the pins outward. Once the pins are released, the strap comes off easily. Insert the new strap by threading the pins into the new holes: the operation is simple if you perform it on a soft surface (a cloth) to avoid scratching the case.

Absolutely yes. Aftermarket straps in 20mm are completely compatible with your Seamaster 120M. In fact, the artisanal market today offers options far more interesting than original straps: superior leather quality, shaped lugs, custom finishes. Just make sure the lug width is exactly 20mm, not 19mm or 21mm.

A leather strap of artisanal quality worn daily generally lasts from 3 to 5 years, but it depends on frequency of use, exposure to moisture/heat and maintenance. With vegetable tanning it ages on purpose, developing patina and character; with chrome tanning it tends to degrade more rapidly. The 18-month warranty on Casati Milano straps covers any manufacturing defects and stitching.