Omega Speedmaster Mark II Co-Axial · Ref. 327.10.43.50.01.001 · 21mm lug · 42.4mm x 46.2mm case
At a Glance
| # | Best For | Strap | Material | Thickness |
|---|---|---|---|---|
| 1 | Overall / First Purchase | Black Epsom Slim Strap | Epsom Calfskin | 2.2mm |
| 2 | Dressy / Formal | Matte Himalayan Alligator Signature Strap | Alligator | 4.5–2.2mm |
| 3 | Everyday / Casual | Grigio Pueblo Slim Strap | Pueblo Calfskin | 2.2mm |
| 4 | Minimalist / Refined | Black Shell Cordovan Slim Strap | Shell Cordovan | 2.2mm |
| 5 | Casual / Relaxed | Fauve Baranil Signature Strap | Baranil Calfskin | 4.5–2.2mm |
| 6 | Active / Sporty | Black CTS Rubber Strap | FKM Rubber | 4.0–3.3mm |
| 7 | Comfort / Wildcard | Natural Babele Slim Strap | Babele Calfskin | 2.2mm |
What makes the Omega Speedmaster Mark II Co-Axial (ref. 327.10.43.50.01.001) special is not just one thing — it is the combination. The automatic movement is the beating heart of this watch — self-winding, reliable, and built to last. Its black dial with orange chronograph seconds hand, cushion-shaped barrel case, tachymeter on inner flange. And at 21mm lug width, it is a watch that rewards experimentation with straps.
The 42.4mm x 46.2mm case with its 14.9mm profile gives you just enough wrist presence to anchor different strap materials without the watch disappearing. Here are my 7 picks — and why each one works.
Quick Specs
| Case diameter | 42.4mm x 46.2mm |
| Lug width | 21mm |
| Lug-to-lug | 50mm |
| Case thickness | 14.9mm |
| Water resistance | 100m |
| Crystal | Domed scratch-resistant sapphire with anti-reflective treatment |
| Case material | Stainless steel |
| Movement | Omega Caliber 3330 (Co-Axial chronograph), automatic, 52h power reserve, chronometer |
The 21mm lug width means your options are curated but well-covered. Already know what you're looking for? Browse all Omega Speedmaster Mark II Co-Axial-compatible straps on the Strap Finder →
1. Best Overall — Black Epsom Slim Strap
Your first strap upgrade should feel like an obvious improvement. This one does.
The Black Epsom Slim Strap features Epsom leather, tanned by Haas. The fine, uniform grain gives it a clean, contemporary look that resists scratches and moisture with ease. This is leather that looks as sharp six months from now as it does on day one. At 2.2mm thick, it balances presence and wearability nicely.
The Omega Speedmaster Mark II Co-Axial's 42.4mm x 46.2mm case is ideally proportioned for this strap. Whether you are wearing it casually or dressing it up, the combination feels intentional. It is the kind of pairing where both the watch and strap look better together than apart.
Simple, effective, and genuinely enjoyable to wear.
2. Best Dressy — Matte Himalayan Alligator Signature Strap
Formal occasions call for something elevated. This delivers without being flashy.
The Matte Himalayan Alligator Signature Strap is crafted from genuine alligator leather — not embossed calfskin, the real thing. Each scale pattern is unique, and the matte finish gives it a refined presence that catches light without being flashy. The leather is supple from the start with minimal break-in needed. At 4.5–2.2mm thick, it balances presence and wearability nicely.
Paired with the Omega Speedmaster Mark II Co-Axial's black dial, this strap adds a layer of personality that the factory option does not offer. The 14.9mm case thickness means a padded strap like this one feels proportional and substantial.
It's the kind of pairing that makes you wonder why you didn't try it sooner.
3. Best Everyday — Grigio Pueblo Slim Strap
The strap you reach for without thinking — that's what an everyday pick should be.
The Grigio Pueblo Slim Strap features Buttero leather from the Walpier tannery in Italy. This vegetable-tanned leather develops one of the most beautiful patinas in watchmaking — scratches blend into the surface and the colour deepens over time. If you enjoy watching your strap age gracefully, this is the one. At 2.2mm thick, it balances presence and wearability nicely.
What makes this pairing work on the Omega Speedmaster Mark II Co-Axial is the contrast — the sporty character of the watch is complemented by the practical construction. With a 42.4mm x 46.2mm case, the proportions stay balanced.
Once you see it on the wrist, it just clicks.
4. Best Minimalist — Black Shell Cordovan Slim Strap
Minimalism isn't about doing less. It's about doing exactly what's needed.
The Black Shell Cordovan Slim Strap is crafted from premium materials with careful attention to detail and construction quality. At 2.2mm thick, it balances presence and wearability nicely.
Paired with the Omega Speedmaster Mark II Co-Axial's black dial, this strap adds a layer of personality that the factory option does not offer. The 14.9mm case thickness means a padded strap like this one feels proportional and substantial.
Once you see it on the wrist, it just clicks.
5. Best Casual — Fauve Baranil Signature Strap
Not every strap needs to make a statement. Sometimes relaxed is the right move.
The Fauve Baranil Signature Strap is crafted from premium materials with careful attention to detail and construction quality. At 4.5–2.2mm thick, it balances presence and wearability nicely.
What makes this pairing work on the Omega Speedmaster Mark II Co-Axial is the contrast — the sporty character of the watch is complemented by the practical construction. With a 42.4mm x 46.2mm case, the proportions stay balanced.
6. Best Sporty — Black CTS Rubber Strap
Sport straps need to perform — water resistance, comfort, durability. This checks every box.
The Black CTS Rubber Strap is made from FKM rubber — a high-performance elastomer that resists chemicals, heat, and ageing. Unlike silicone, it does not attract dust or lint. Cut-to-size construction means you trim it to your exact wrist measurement — no leftover tail, no keepers. At 4.0–3.3mm thick, it balances presence and wearability nicely.
What makes this pairing work on the Omega Speedmaster Mark II Co-Axial is the contrast — the sporty character of the watch is complemented by the practical construction. With a 42.4mm x 46.2mm case, the proportions stay balanced.
Simple, effective, and genuinely enjoyable to wear.
7. The Wildcard — Natural Babele Slim Strap
Think of this as the strap you didn't know you needed.
The Natural Babele Slim Strap features Buttero leather from the Walpier tannery in Italy. This vegetable-tanned leather develops one of the most beautiful patinas in watchmaking — scratches blend into the surface and the colour deepens over time. If you enjoy watching your strap age gracefully, this is the one. At 2.2mm thick, it balances presence and wearability nicely.
The Omega Speedmaster Mark II Co-Axial's 42.4mm x 46.2mm case is ideally proportioned for this strap. Whether you are wearing it casually or dressing it up, the combination feels intentional. It is the kind of pairing where both the watch and strap look better together than apart.
The kind of strap that earns a permanent spot in your rotation.
A Note on Buckle Colour
Quick but important: always match your buckle to your case. The Omega Speedmaster Mark II Co-Axial's Stainless steel case calls for a silver (brushed or polished) buckle. All Delugs leather straps ship with a pin buckle and can be upgraded to a Spring Deployant Clasp for extra security and convenience. All Delugs straps come with quick-release spring bars pre-installed, so swapping straps takes seconds.
How to Change the Strap on Your Omega Speedmaster Mark II Co-Axial
Swapping straps on the Omega Speedmaster Mark II Co-Axial is one of the easiest upgrades you can make — and with Delugs straps, you don't even need a tool.
If your Omega Speedmaster Mark II Co-Axial came on a bracelet, you'll first need to remove it. The easiest way to do this at home is with a Bracelet Removal Tool, which lets you compress the spring bars without risking scratches to the lugs or caseback. Once the bracelet is off, you can slide your new Delugs strap straight in.
All Delugs straps come with quick-release spring bars already pre-installed, so changing straps is completely tool-free. Here's how:
- Prepare your workspace. Lay the watch face-down on a soft cloth or microfiber pad to protect the caseback from scratches.
- Release the spring bar. Locate the small lever on the quick-release spring bar. Pull it back with your fingernail or fingertip to compress the bar.
- Remove the strap. While holding the lever, angle the strap out from between the lugs. Repeat for the other side.
- Insert the new strap. Slide one end of the spring bar into the lug hole. Pull the lever on the quick-release spring bar knob, guide the entire spring bar into the opposite lug hole, and then release the knob. You should hear a small click when the spring bar extends and seats into the lug hole.
- Check the fit. Give the strap a gentle tug to make sure both spring bars are securely locked in. If there's any play, reseat the spring bar.
The entire process takes under a minute once you get the hang of it — no spring bar tool required. The Omega Speedmaster Mark II Co-Axial uses a standard 21mm lug width, and all Delugs straps in 21mm will fit perfectly.
Frequently Asked Questions
What is the lug width of the Omega 327.10.43.50.01.001?
The Omega 327.10.43.50.01.001 has a 21mm lug width. While 21mm is less common than 20mm, there is still a strong selection of quality straps available. All Delugs straps are available in 21mm.
What is the reference number for the Omega Speedmaster Mark II Co-Axial?
The reference number for the Omega Speedmaster Mark II Co-Axial is 327.10.43.50.01.001. You can find this on the caseback of your watch or on the original paperwork. Knowing your reference number helps ensure you get the right lug width when ordering a strap.
Can I use a dressy leather strap on a Omega sport watch?
Yes — and it's a surprisingly good combination. Putting the Speedmaster Mark II Co-Axial on a leather strap, especially something like an alligator or saffiano, dresses it up for occasions where a bracelet or rubber might feel too casual. The contrast between a sport watch and a refined strap can be striking.
Do Delugs straps come with spring bars?
Yes — every Delugs strap comes with quick-release spring bars pre-installed. This means you can change straps by hand in seconds, without needing any tools. The quick-release mechanism uses a small lever that you pull with your fingertip to compress the spring bar.
What is the best strap material for the Omega Speedmaster Mark II Co-Axial?
For the Speedmaster Mark II Co-Axial, rubber and sailcloth are excellent starting points — waterproof, durable, and purpose-built for active wear. If you want to dress it up, waxy or nubuck leather straps add character while remaining practical. Browse the Strap Finder to see all compatible options.
Does Omega use quick-release spring bars?
Most Omega watches use standard spring bars that require a tool to remove. All Delugs straps come with quick-release spring bars pre-installed, so once you make the switch, future changes are completely tool-free.
Where can I find straps compatible with the Omega 327.10.43.50.01.001?
The Omega Strap Finder shows every Delugs strap compatible with the 327.10.43.50.01.001, filtered by lug width and style. You can also use the general Strap Finder to browse by brand, collection, and material. If you need help choosing, our team is available 24/7 via live chat.
Finding Your Strap
The beauty of the Omega Speedmaster Mark II Co-Axial is that it rewards experimentation. Leather one day, rubber the next — each strap brings out a different side of the watch.
Use the Omega Speedmaster Mark II Co-Axial Strap Finder to see every compatible strap in one place, filtered to your exact reference. Or if you'd rather explore by feel, the general Omega Strap Finder lets you browse the full lineup and find your match.
Not sure which strap is right for your specific Speedmaster Mark II Co-Axial? Our team is available 24/7 via live chat — drop us a message and we'll help you find the perfect match for your watch, wrist size, and style.
About Delugs
Founded in 2018 and headquartered in Singapore, Delugs is dedicated to elevating the experience of watch ownership through the simple yet powerful act of strap changing. We believe that straps are integral to how a timepiece is worn, perceived, and enjoyed. Our mission is to make strap changing a lifestyle — an everyday act of self-expression and versatility.
Delugs is an independent brand with a global community of clients, with a strong online presence and growing physical retail footprint. Our direct-to-consumer focus keeps us closely connected with the watch enthusiast community — fostering conversations, hosting events, and helping shape a more inclusive and expressive culture around watch collecting. We also work closely with watch brands to craft straps that complement their timepieces, bridging the gap between brand and collector, form and function.
Our catalogue spans leather, rubber, and fabric straps, with options for every watch and every occasion. We are committed to craftsmanship and quality, product design and innovation, and outstanding customer service. We offer watch owners the freedom to change straps as easily as changing outfits, and the opportunity to engage more deeply with the watches they love.
Visit our flagship boutique at Raffles Hotel, Singapore →
— Marcus
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