Omega · Seamaster 120M
Strap for Seamaster 120M Quartz 41 Stainless Steel / Yellow Gold / Champagne / Bracelet
Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.
Lug width
Straps for the Seamaster 120M 2311.11.00
Selected for the 20 mm lug width · workshop selection
Military Red Alligator Strap with Blue Stitching€183
Black and Red NATO Strap — Military Heritage€183
Black Crocodile Military Strap with Blue Stitching€183
Black Calfskin NATO Strap 20mm€80
Dark Brown Calfskin Military Strap€80
The Seamaster 120M 2311.11.00, seen from the bench
Frequently asked questions
What is the lug width of the Seamaster 120M 2311.11.00?
The Seamaster 120M reference 2311.11.00 features a lug width of exactly 20 millimetres. This measurement can be verified with a digital calliper positioned perpendicularly to the case, between the inner points of one lug to the other, and remains consistent across all examples of this reference produced by Omega.
What is the best strap for the Seamaster 120M 2311.11.00?
There is no single choice: it depends on usage. For aesthetic versatility, dark brown alligator combines elegance with the diving theme. For durability in marine environments, FKM rubber or neoprene guarantee salt resistance and rapid drying. For those ageing the watch over time, shell cordovan develops an incomparable natural patina. Vegetable-tanned alligator represents the sustainability-longevity compromise.
How do you change the strap on an Omega Seamaster 120M?
The strap is removed by sliding it out from the lugs using dedicated precision tools (spring bar tool). Position the watch flat, locate the through-hole on the lug, insert the tool into the internal elastic spring, decompress and extract the fastening bar. Repeat for the opposite lug. Installation of the new strap follows the reverse process: insert the strap lug ends into the holes and verify perpendicular alignment with the case.
Is an aftermarket strap compatible with the Seamaster 120M 2311.11.00?
Yes, provided the strap is sized for a 20mm lug width. Bespoke and industrial straps at this width mount without modifications to the case. Always verify that the lug thickness matches your desired visual proportions: straps that are too thin appear inadequate for a 41mm diameter, while excessively thick ones compromise the sporting elegance typical of this Seamaster.
How long does a leather strap last on an Omega Seamaster 120M?
Durability varies based on material, usage and care. Alligator and vegetable-tanned calf guarantee 4-6 years of moderate daily use before requiring replacement. Shell cordovan can exceed 7-8 years if exposed moderately to humidity. FKM rubber straps last 3-4 years in frequent marine environments. Regular maintenance—cleaning, drying and light conditioning—significantly extends operational lifespan.
The next step
The right strap isn't chosen. It is built, together.
From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.
Request an appointment →Casati Milano · Via XX Settembre 15, Milan · by appointment only

