The watch identified by this title is the Roger Dubuis Excalibur Monotourbillon Cobalt 42mm, reference RDDBEX0838. It pairs a manually wound skeleton flying monotourbillon with a 42mm cobalt case and a stated 72-hour power reserve. The specifications below are published by Roger Dubuis; they are not the result of an independent hands-on inspection or wear test.
What are the specifications of the RDDBEX0838?
Roger Dubuis lists the following details for the Excalibur Monotourbillon Cobalt 42mm on its official product page (publication date not stated).
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| Specification | RDDBEX0838 |
|---|---|
| Model | Excalibur Monotourbillon Cobalt 42mm |
| Reference | RDDBEX0838 |
| Case | Cobalt CarTech Micro-Melt BioDur CCMTM |
| Case diameter | 42mm |
| Crystal and caseback | Sapphire crystal with anti-reflective coating; transparent cobalt caseback with sapphire crystal |
| Water resistance | 10 bar (100m), as stated by Roger Dubuis |
| Movement | RD512, manually wound skeleton flying monotourbillon |
| Power reserve | 72 hours, as stated by Roger Dubuis |
| Movement components and jewels | 194 components; 19 jewels |
| Movement frequency | 21,600 vibrations per hour |
| Movement dimensions | 16mm diameter; 6.9mm thickness |
| Dial and flange | Blue CVD-coated double-surface flange, engraved minute track and transferred text; polished, rhodium-plated hour markers with SLN in the center |
| Strap | Blue calf leather with Quick Release System (QRS) |
| Clasp | Titanium cover and blades, triple folding, interchangeable through QRS |
What stands out about the case and dial?
Cobalt case and display back
The 42mm case is specified as cobalt CarTech Micro-Melt BioDur CCMTM. Roger Dubuis pairs it with a sapphire crystal and a transparent cobalt caseback with sapphire crystal, so the movement is visible from the back as well as through the skeletonized display. The listed 10-bar (100m) water resistance is a manufacturer specification, not an independent verification of real-world performance.
Blue flange and legibility details
The blue CVD-coated flange has two surfaces, an engraved minute track and transferred text. Polished, rhodium-plated hour markers have SLN in the center. These are the dial details in the brand’s listing; no independent assessment of low-light legibility is available here.
#1 Best Overall
- resistant with aging：Genuine leather becomes more resistant and develops a patina over time. It can withstand daily use and maintain its quality.
- Luxurious Genuine Leather：Crafted from top - grade genuine leather, this strap exudes . The natural texture offers a rich and sophisticated look.
- Customizable Fit：Equipped with multiple holes, it can be easily adjusted to fit different wrist sizes, ensuring a and secure fit.
- Soft & ComfortableThe leather is soft to the touch, conforming to the wrist for a comfortable fit. It provides a pleasant wearing experience throughout the day.
- Classic Design：With a timeless design, it complements various watch styles. Whether a classic or watch, it adds an elegant touch.
What is inside the RD512 movement?
The RD512 is a manual-winding skeleton flying monotourbillon movement. Roger Dubuis describes its main plate and bridges as shot-blasted and trued-up, with NAC or blue CVD coating. The brand states a 72-hour reserve and lists 194 components, 19 jewels, a frequency of 21,600 vibrations per hour, a 16mm diameter and 6.9mm thickness.
“Power reserve: 72 Hours” is the wording used on the official product page. It is a published specification, not a measured result from a timing or power-reserve test.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How does it differ from the 45mm Double Tourbillon Cobalt?
Roger Dubuis also lists a separate Cobalt model: the 45mm Excalibur Double Tourbillon Cobalt, reference RDDBEX1109. Its larger case and two-tourbillon construction make it a different watch, not another specification set for RDDBEX0838.
| Detail | Monotourbillon Cobalt | Double Tourbillon Cobalt |
|---|---|---|
| Reference | RDDBEX0838 | RDDBEX1109 |
| Case diameter | 42mm | 45mm |
| Tourbillon configuration | One flying monotourbillon | Two flying tourbillons linked by a differential |
| Calibre | RD512 | RD108 |
| Component count | 194 | 319 |
| Jewels | 19 | 32 |
| Power reserve | 72 hours, stated by the manufacturer | 72 hours, stated by the manufacturer |
The Double Tourbillon figures come from Roger Dubuis’s official RDDBEX1109 product page. Its RD108 specifications should not be attributed to the 42mm RDDBEX0838.
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1Clear out junk files and repair common Windows errors2Scan for outdated or missing drivers - takes under a minute3Repair Windows errors before they cause bigger problemsWhat should buyers confirm before purchasing?
The official RDDBEX0838 product details reviewed do not state a price or market availability. Both can vary by location, so ask Roger Dubuis or a market-specific authorized retailer to confirm current production status, availability and pricing before making a purchase.
The listed strap is blue calf leather and uses QRS, as does the titanium triple-folding clasp. Roger Dubuis’s product details do not state the strap width, lug measurement, exact replacement strap reference or third-party compatibility. Confirm fit and replacement-part details with the brand or an authorized retailer rather than assuming that a particular aftermarket strap will fit.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
