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What “hypocycloidal” means on the CHPTR_Δ
BA111OD describes a satellite hour wheel rolling around a fixed central hour wheel. The mechanism uses a deltoid cycloid with a 1/3 ratio, causing the tip of the hour hand to trace a triangle as it indicates the hours. The minute hand continues along a circular path, so the two indications follow visibly different geometries.
This account follows the maker’s explanation; it is not an independently verified teardown. The Federation of the Swiss Watch Industry also described the watch’s circular-minute and hypocycloidal-hour display in June 2023, crediting Olivier Mory with technical development and production work: Federation of the Swiss Watch Industry, June 2023. BA111OD calls the design a “world premiere,” but that remains the brand’s characterization rather than an independently established distinction.
Who developed it—and what the movement is
BA111OD developed the complication with watchmaker Olivier Mory. On the CHPTR_Δ.2 [B.ROK], the manufacturer specifies an automatic Swiss Made movement using its module 09310 on a Soprod M100 base, with a stated 42-hour power reserve. That means the module is a BA111OD component, but the listed base is Soprod’s; the specification does not support describing the entire movement as designed and manufactured in-house. The brand’s mechanism explanation appears on its CHPTR_Δ collection page.
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CHPTR_Δ models and published specifications
The range includes different case sizes, finishes and bracelet or strap options. The figures below are model-specific, not specifications shared by every CHPTR_Δ. Prices are those displayed by BA111OD when accessed in 2026 and can change.
| Model | Case and configuration | Published specifications | Price and status |
|---|---|---|---|
| CHPTR_Δ.2 [B.ROK] | 44 mm 316L stainless steel; rubber strap with deployant clasp and easy strap exchange | 12.9 mm thick including glass; 46 mm lug-to-lug; 5 ATM water resistance; date at 2 o’clock; domed antireflective sapphire; automatic Swiss Made movement with BA111OD module 09310 on a Soprod M100 base; 42-hour power reserve | CHF 2,800 displayed by BA111OD when accessed in 2026. Manufacturer product page |
| CHPTR_Δ.9 2-Tone | 40 mm steel case with yellow-gold PVD coating; bracelet or rubber-strap versions | 42-hour power reserve; 5 ATM water resistance | CHF 2,950 displayed by BA111OD when accessed in 2026. Manufacturer product page |
| CHPTR_Δ MDP | 40 mm format; BA111OD says it retains the original 44 mm model’s architecture and identity | Not stated in the cited announcement | One-off series of 30 pieces announced September 25, 2026. Manufacturer announcement |
How to choose between the sizes and finishes
Start with the case dimensions and wearing configuration rather than assuming one model’s specifications carry over to another. The 44 mm CHPTR_Δ.2 [B.ROK] is the larger steel option in the cited listings; the CHPTR_Δ.9 2-Tone has a 40 mm case with yellow-gold PVD coating. The MDP announcement identifies another 40 mm version, but does not provide a full specification list in the cited material.
Rank #2
- [Luxurious Mechanical Watch] High quality hollow mechanical watch appearance retro gorgeous, exquisite carving and design of the golden appearance of the European nobility more highlight your noble identity extraordinary taste, to bring you a pleasant luxury experience
- [Mechanical Movement] This watch has manual self-winding. Please consider that mechanical watches that require manual winding can only keep time for a short time after winding. To prevent running or inaccurate time, it is advised that you verify the time periodically and wind up the chain 15–20 times.
- [Waterproof] Water resistant to 50m (165ft) -suitable for short periods of recreational swimming and showering, but not diving or snorkeling
- [Ideal as a Gift] This beautiful retro-style watch can be worn on any occasion or given as a gift to your father, brother, partner, or boyfriend. At weddings and any holiday gatherings, it can be a really appreciated and elegant gift.
- [Professional After-Sale Service] Please contact us if you need any additional details about our watches. We will be happy to answer and help you anytime.
- Check the exact reference: BA111OD’s pages list model-specific cases and specifications. Confirm the reference before relying on details such as thickness, date display or crystal.
- Check the wearing configuration: The cited CHPTR_Δ.2 [B.ROK] listing specifies a rubber strap; the CHPTR_Δ.9 2-Tone page offers bracelet or rubber versions.
- Verify current price and availability: The CHF amounts above are manufacturer-displayed prices accessed in 2026, not a guarantee of today’s price or stock.
What the specifications can—and cannot—tell you
BA111OD lists 5 ATM water resistance for the CHPTR_Δ.2 [B.ROK] and CHPTR_Δ.9 2-Tone. That is a published rating, not evidence here of a particular swimming or diving test, and it should not be treated as a general durability verdict. The available specifications also do not establish long-term reliability, servicing costs or how the watch performs in everyday wear. Those questions require evidence beyond the manufacturer’s product information.
Quick Recap
Best Value
- [Luxurious Mechanical Watch] High quality hollow mechanical watch appearance retro gorgeous, exquisite carving and design of the golden appearance of the European nobility more highlight your noble identity extraordinary taste, to bring you a pleasant luxury experience
Rank #4
- CLASSIC WHITE DIAL WITH BLUE HANDS – Clean white dial with striking blue hands and bold Arabic numerals for easy reading at a glance. Vintage-inspired design that draws compliments. A timeless aesthetic that works equally well for business or casual wear. 40mm case size offers substantial wrist presence without being overwhelming
- AUTOMATIC SELF-WINDING MOVEMENT – Powered by wrist motion during wear, no battery needed. Manual winding available as backup for occasional use. For optimal performance, wear regularly or hand-wind 15-20 turns daily. Note: Power reserve may not last overnight without regular wear or winding
- SCRATCH-RESISTANT MINERAL GLASS – Reinforced mineral crystal resists scratches and scuffs from daily wear. Clear exhibition case back lets you view the intricate mechanical movement. Durable construction for reliable everyday use
- COMFORTABLE BROWN PU LEATHER STRAP – Soft, flexible PU leather strap designed for all-day comfort. Adjustable buckle closure fits most wrist sizes. 20mm strap width complements the classic dial design. (Note: For extended durability, avoid prolonged exposure to moisture.)
- VERSATILE & EASY-TO-READ DESIGN – Bold numerals and contrasting blue hands ensure quick time reading in various lighting conditions. 13mm slim profile fits comfortably under shirt cuffs. Ideal for work, weekends, travel, or casual outings. 3ATM splash-resistant for hand-washing and light rain
Rank #3
- Material: Mechanical movement, mineral strengthened glass mirror, the case is made of stainless steel and the strap is made of High grade leathe.
- Measuare: Band length: 18.5cm/7.39inch, dial diameter: 41mm/1.6inch, dial thickness: 15mm/0.6inch.
- 30M waterproof, Daily waterproofing to prevent water splashing. But not suitable for bathing and swimming.
- Classic and fashionable desgin, PU leather strap, suitable for any occasion.
- It will be a wonderful gift for your father, husband, friends, son or brother on some special days.
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.
