Sinn 105 St Sa · Ref. 105.020 · 20mm lug · 41mm case
At a Glance
| # | Best For | Strap | Material | Thickness |
|---|---|---|---|---|
| 1 | Overall / First Purchase | Colibri Chevre Slim Strap | Chèvre | 2.2mm |
| 2 | Dressy / Formal | Glossy Lagoon Blue Crocodile Signature Strap | Crocodile | 4.5–2.2mm |
| 3 | Everyday / Casual | Green Buttero Slim Strap | Buttero Calfskin | 2.2mm |
| 4 | Minimalist / Refined | Green Shell Cordovan Slim Strap | Shell Cordovan | 2.2mm |
| 5 | Casual / Relaxed | Navy Rubberised Leather (Togo) Signature Strap | Togo Leather (Rubberised) | 4.5–2.2mm |
| 6 | Active / Sporty | Black Tropical CTS Rubber Strap | FKM Rubber (Tropical) | 4.0–3.3mm |
| 7 | Comfort / Wildcard | Warm Grey Hook Strap [kollokium x Delugs] | Fabric | 1.3mm |
The Sinn 105 St Sa (ref. 105.020) is one of those watches that makes you stop and look — and then look again. The finishing and attention to detail speak for themselves. At 20mm lug width, it is an incredibly versatile canvas for strap changes.
The 41mm case with its 11.9mm 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 | 41mm |
| Lug width | 20mm |
| Lug-to-lug | 47.4mm |
| Case thickness | 11.9mm |
| Water resistance | 200m |
| Crystal | Sapphire |
| Case material | Stainless steel |
| Movement | Sellita SW220-1 |
The 20mm lug width means your options are curated but well-covered. Already know what you're looking for? Browse all Sinn 105 St Sa-compatible straps on the Strap Finder →
1. Best Overall — Colibri Chevre Slim Strap
If you're buying your first aftermarket strap for the Sinn 105 St Sa, this is where I'd start.
The Colibri Chevre Slim Strap is made from chevre (goatskin) leather, sourced from the Alran tannery. The natural pebbled grain is finer than Epsom and slightly shiny — it looks luxurious without trying too hard. Chevre is also impressively water and scratch resistant for a natural leather. At 2.2mm thick, it balances presence and wearability nicely.
On the Sinn 105 St Sa, this strap preserves the watch's go-anywhere character. The 41mm case at 11.9mm thick pairs naturally with the padded construction without creating any imbalance on the wrist.
Once you see it on the wrist, it just clicks.
The range goes deeper if you want to explore:
- Light Grey Chevre Slim Strap
- Lavender Chevre Slim Strap
- Gold Chevre Slim Strap
- Red Chevre Slim Strap
2. Best Dressy — Glossy Lagoon Blue Crocodile Signature Strap
The Sinn 105 St Sa cleans up remarkably well — and this strap is the reason.
The Glossy Lagoon Blue Crocodile Signature Strap is made from genuine crocodile leather with a distinctive scale pattern that no embossed leather can replicate. The texture adds visual depth and character that works equally well with a suit or a smart-casual outfit. At 4.5–2.2mm thick, it balances presence and wearability nicely.
What makes this pairing work on the Sinn 105 St Sa is the contrast — the refined case finishing against the texture creates visual interest without conflict. With a 41mm case, the proportions stay balanced.
Simple, effective, and genuinely enjoyable to wear.
Alternatives in the same family:
- Glossy Caramel Crocodile Signature Strap
- Glossy Emerald Crocodile Signature Strap
- Glossy Taupe Brown Crocodile Signature Strap
- Glossy Grey Crocodile Signature Strap
3. Best Everyday — Green Buttero Slim Strap
An everyday strap needs to be comfortable from the jump and work with most of what you wear.
The Green Buttero 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.
On the Sinn 105 St Sa, this strap preserves the watch's go-anywhere character. The 41mm case at 11.9mm thick pairs naturally with the padded construction without creating any imbalance on the wrist.
Simple, effective, and genuinely enjoyable to wear.
Alternatives in the same family:
- Chestnut Buttero Slim Strap
- Brown Buttero Slim Strap
- Taupe Buttero Slim Strap
- Natural Buttero Slim Strap
4. Best Minimalist — Green Shell Cordovan Slim Strap
Clean lines and no visual clutter — that's the appeal here.
The Green 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.
What makes this pairing work on the Sinn 105 St Sa is the contrast — the refined case finishing against the texture creates visual interest without conflict. With a 41mm case, the proportions stay balanced.
Other colours worth considering:
- Black Shell Cordovan Slim Strap
- Navy Shell Cordovan Slim Strap
- Cognac Shell Cordovan Slim Strap
- Natural Shell Cordovan Slim Strap
5. Best Casual — Navy Rubberised Leather (Togo) Signature Strap
Not every strap needs to make a statement. Sometimes relaxed is the right move.
The Navy Rubberised Leather (Togo) Signature Strap uses rubberised leather — a material that blends the look and feel of leather with the water resistance and durability of rubber. The smooth finish is clean and modern, and the pastel colour options add a playful element to otherwise serious watches. At 4.5–2.2mm thick, it balances presence and wearability nicely.
What makes this pairing work on the Sinn 105 St Sa is the contrast — the refined case finishing against the texture creates visual interest without conflict. With a 41mm case, the proportions stay balanced.
Other colours worth considering:
- Black Rubberised Leather (Togo) Signature Strap
- Colibri Rubberised Leather (Togo) Signature Strap
- Hunter Green Rubberised Leather (Togo) Signature Strap
- Taupe Rubberised Leather (Togo) Signature Strap
6. Best Sporty — Black Tropical CTS Rubber Strap
When you want your Sinn 105 St Sa to feel more relaxed and sporty, this is the pick.
The Black Tropical 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.
On the Sinn 105 St Sa, this strap preserves the watch's go-anywhere character. The 41mm case at 11.9mm thick pairs naturally with the padded construction without creating any imbalance on the wrist.
Alternatives in the same family:
7. The Wildcard — Warm Grey Hook Strap [kollokium x Delugs]
![Warm Grey Hook Strap [kollokium x Delugs] on Sinn 105 St Sa](https://cdn.shopify.com/s/files/1/0054/9040/9585/files/20250919-A7405207.jpg?v=1761299094&width=800)
This one's different — and that's exactly the point.
The Warm Grey Hook Strap [kollokium x Delugs] is crafted from premium materials with careful attention to detail and construction quality. At 1.3mm thick, it balances presence and wearability nicely.
![Warm Grey Hook Strap [kollokium x Delugs]](https://cdn.shopify.com/s/files/1/0054/9040/9585/files/Kollokium_straps_Warm_Grey_1.jpg?v=1761299094)
On the Sinn 105 St Sa, this strap preserves the watch's go-anywhere character. The 41mm case at 11.9mm thick pairs naturally with the padded construction without creating any imbalance on the wrist.
Alternatives in the same family:
- Anthracite Hook Strap [kollokium x Delugs]
- Black Hook Strap [kollokium x Delugs]
- Khaki-Green Hook Strap [kollokium x Delugs]
- Orange Hook Strap [kollokium x Delugs]
A Note on Buckle Colour
Quick but important: always match your buckle to your case. The Sinn 105 St Sa'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 Sinn 105 St Sa
Swapping straps on the Sinn 105 St Sa is one of the easiest upgrades you can make — and with Delugs straps, you don't even need a tool.
If your Sinn 105 St Sa 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 Sinn 105 St Sa uses a standard 20mm lug width, and all Delugs straps in 20mm will fit perfectly.
Frequently Asked Questions
What is the lug width of the Sinn 105.020?
The Sinn 105.020 has a 20mm lug width. While 20mm is less common than 20mm, there is still a strong selection of quality straps available. All Delugs straps are available in 20mm.
What is the reference number for the Sinn 105 St Sa?
The reference number for the Sinn 105 St Sa is 105.020. 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 Sinn versatile watch?
The 105 St Sa is one of the most versatile watches in the Sinn lineup — it takes both dressy and casual straps equally well. That's part of what makes it such a rewarding watch for strap changes. Don't be afraid to experiment.
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 Sinn 105 St Sa?
The 105 St Sa's versatile nature means it works with almost everything. Start with what matches your most common wearing occasion — rubber or sailcloth for active use, nubuck or waxy leather for everyday, and alligator or saffiano for dressier moments. The Strap Finder makes it easy to browse by material and style.
Does Sinn use quick-release spring bars?
Most Sinn 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 Sinn 105.020?
The Sinn Strap Finder shows every Delugs strap compatible with the 105.020, 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 Sinn 105 St Sa is that it rewards experimentation. A dressy alligator for the office, nubuck for the weekend — each strap brings out a different side of the watch.
Use the Sinn 105 St Sa 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 Sinn Strap Finder lets you browse the full lineup and find your match.
Not sure which strap is right for your specific 105 St Sa? 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
![Anthracite Hook Strap [kollokium x Delugs] - Image 2](http://delugs.com/cdn/shop/files/20250919-A7405309_298x298_crop_center.jpg?v=1761299094)
![Delugs Anthracite Hook Strap [kollokium x Delugs] Fabric Watch Strap](http://delugs.com/cdn/shop/files/Kollokium_straps_Anthracite_1_298x298_crop_center.jpg?v=1761299094)
