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The BALL Roadmaster M Model A pairs two uncommon complications: a mechanical alarm and a GMT display. Its second crown winds and sets the alarm, while the main crown handles the watch and date; a rotating 24-hour bezel extends the GMT display to a third time zone. The combination is distinctive, but the 41 mm case is 15.2 mm thick, the dial has a real scale-reading compromise, and water resistance is reduced when the alarm crown is unscrewed.
What the alarm and GMT controls do
The Roadmaster M Model A brings together hours, minutes, seconds, date, a mechanical alarm, and GMT. BALL says the GMT hand, 24-hour scale, and bidirectional 24-hour bezel can be used to indicate up to three time zones. This is a reading aid rather than a complication that automatically adjusts for time zones: the wearer sets and interprets the indications.
| Control or feature | What it does |
|---|---|
| Crown at 2 o’clock | Sets timekeeping functions, the date, and GMT. |
| Crown at 4 o’clock | Winds and sets the alarm, and switches it on or off. |
| GMT hand and 24-hour scale | Show a second time-zone indication. |
| Bidirectional 24-hour bezel | Can be used with the GMT display to track a third time zone, according to BALL. |
The alarm is mechanical, not an electronic beep. BALL describes a separate alarm spring storing energy for the alarm; when it sounds, a hammer strikes a gong. The manufacturer says the gong was lengthened to extend resonance and that openings below the dial help the sound carry. Fratello reviewer Jorg Weppelink found the sound crisp and reported that it rang for up to 18 seconds; that duration is his review observation, not a manufacturer guarantee. BALL Japan characterizes its mechanical alarm tone as nostalgic, which is the maker’s description rather than an independent assessment.
Wearing the 41 mm case
BALL lists the case as 41 mm in diameter and 15.2 mm thick. The Japanese classic-style reference is approximately 189 g, and Fratello reports a 48.5 mm lug-to-lug measurement. Together, the thickness and weight give the watch substantial wrist presence; the diameter alone does not tell the whole fit story.
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- DG3030B-S3C-BR
- Chronometer
- GMT
- Day/Date
- Water Resistant
Weppelink describes the case as substantial and potentially less suited to smaller wrists, while saying the curved lugs and ergonomics made it more wearable than he expected. That is one reviewer’s experience, not a guarantee of fit. If possible, try the watch on: lug-to-lug length, thickness, and the weight on your chosen strap or bracelet can matter as much as diameter.
Dial readability and illumination
The dial has to accommodate conventional timekeeping, date, alarm, and GMT information. webChronos describes the layout as complex but organized, while pointing out two specific reading issues: the minute hand can cover part of the scale, and the logo printed on the sapphire crystal can overlap minute markers when viewed at an angle. Those details may matter if you expect to make frequent precise readings from the peripheral scales.
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BALL specifies 29 self-luminous micro gas tubes on the hands and dial. The tubes glow continuously without needing to be charged by light, according to the manufacturer. The bezel uses Super-LumiNova instead, which benefits from exposure to light; it is a separate illumination system.
Water resistance and durability claims
BALL specifies 100 m water resistance when the crowns are screwed in. Its Japanese product page says water resistance is reduced to everyday-life protection when the alarm is engaged and the alarm crown is unscrewed. Do not treat the 100 m figure as applying with that crown open. Check that the crowns are secured before exposing the watch to water, and follow BALL’s instructions for the alarm setting.
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The manufacturer also specifies 5,000 G shock resistance and 4,800 A/m anti-magnetism, along with a sapphire crystal. BALL Japan frames the shock test as equivalent to a one-meter fall onto a wooden floor. These are manufacturer specifications and test framing, not a claim that the watch is indestructible.
Movement, edition, and specifications
Movement naming varies by source and market presentation: BALL materials use RR7379, while RRM7379 also appears. webChronos reports 31 jewels, a frequency of 28,800 vibrations per hour, and approximately 45 hours of power reserve. Treat the reserve as that publication’s reported specification rather than a verified manufacturer guarantee. Fratello describes the movement as having two mainsprings and the alarm/GMT mechanism. BALL Japan says development took approximately three years.
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- GMT
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| Specification | Published information |
|---|---|
| Case | 904L stainless steel; 41 mm diameter; 43.5 mm bezel diameter; 15.2 mm thick (BALL). Fratello reports 48.5 mm lug-to-lug. |
| Weight | Approximately 189 g for the Japanese classic-style version (BALL Japan). |
| Movement | BALL caliber RR7379/RRM7379 naming varies by source and market. webChronos reports 31 jewels, 28,800 vph, and approximately 45 hours of power reserve. |
| Functions | Mechanical alarm, GMT, date, hours, minutes, and seconds; BALL says the GMT and bezel arrangement can indicate up to three time zones. |
| Lighting | 29 self-luminous micro gas tubes on hands and dial; Super-LumiNova on the bezel (BALL). |
| Water resistance | 100 m with crowns screwed in (BALL); reduced to everyday-life water resistance with the alarm engaged and alarm crown unscrewed (BALL Japan). |
| Edition | 333 pieces worldwide, according to BALL’s official product page. |
The source set does not establish chronometer certification for this model.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Price and availability depend on market
The references and offers below are regional snapshots, not interchangeable SKUs or a universal current price. BALL’s US page identifies reference DA9100C-S1-BKR. The US official listing returned in the reviewed material showed US$6,899 including import duties and six-month availability. BALL Japan identifies the classic-style watch as DA9100C-S1J-BK and lists it at ¥990,000 including tax as a 333-piece worldwide edition. Its product page described assembly to order and estimated delivery around early October 2026; that estimate is time-sensitive and may have changed.
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Before buying, check the exact reference, local tax treatment, stock status, delivery estimate, and service arrangements with BALL or an authorized local retailer. The reviewed sources do not establish Amazon stock or an affiliate offer.
Who the Roadmaster M Model A suits
The model is most compelling for someone who specifically wants a mechanical alarm alongside GMT and is willing to learn a busier dial. The alarm is a tactile, mechanical alternative to an electronic alert, but its usefulness depends on whether you will actually rely on a wristwatch alarm. Weppelink enjoyed operating it during his short review period but questioned whether owners would use it as often over the long term.
- Consider it if: the mechanical alarm is a feature you genuinely want, you will use the GMT and bezel indications, and a thick, substantial watch suits your wrist.
- Think carefully if: you need quick, precise reading from every dial scale, prefer a lighter or slimmer watch, or expect the 100 m rating to apply while the alarm crown is unscrewed.
These trade-offs are more useful than a broad value verdict: the available reviews do not provide a like-for-like competitor comparison, and regional prices and availability differ.
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.
