Committed to producing just 299 watches each year, the Swiss independent brand Brellum is very much a small-scale operation, though I consistently find myself impressed by the quality and attention to detail among its products. A considerable portion of Brellum’s contemporary catalog is based upon its signature DuoBox case, and this serves as the foundation for related models such as the Pandial and Pilot series. Expanding upon this core platform for its latest release of 2024 is the Brellum Duobox Triple Calendar Moonphase Chronometer, which offers a full suite of calendar complications and will be produced as a limited edition of just 46 examples.

From an external standpoint, the case of the new Brellum Duobox Triple Calendar Moonphase Chronometer is more-or-less identical to what can be found on the brand’s Pilot LE.2 GMT that I previously reviewed. Crafted from stainless steel with brushed and polished surfaces, the case measures 41.8mm in diameter by 11.7mm thick, with 22mm lugs and an overall lug-to-lug profile of approximately 51.6mm. Once you factor in the pair of box-shaped sapphire crystals that are fitted to either side of the watch, the overall height of the Duobox Triple Calendar Moonphase comes in at 15.9mm (the same as the Pilot GMT series), and while this on-paper measurement is admittedly rather thick, the curvature of the caseback combined with the pair of box-shaped crystals goes a long way toward decreasing the visual height of the watch and allowing it to sit comfortably on the wrist.

Similar to the brand’s Pilot GMT models, the Brellum Duobox Triple Calendar Moonphase LE Chronometer features a thin polished bezel sounding its crystal, while the right-hand side of the case is furnished by a signed winding crown flanked by a set of pump-style chronograph pushers. The weight of the watch comes in at a total of 112 grams (including its strap), and just like the rest of Brellum’s models that use its signature Duobox case, water resistance is a solid 100 meters to protect against most forms of moisture contact. With that in mind, the one key detail that separates the case of the new Brellum Duobox Triple Calendar Moonphase from those of its Pilot GMT siblings is the inclusion of a small push-piece that sits recessed into the side of the case at 10 o’clock, and this is used to adjust day display on the watch.

As the most dressy and formal model that is based upon the Duobox case, the Brellum Duobox Triple Calendar Moonphase has a dial that is noticeably more refined than what you will find among watches from the Pandial or Pilot collections, and it largely follows the blueprint established by the Brellum Duobox LE.4 from 2019. Featuring a slightly recessed white outer ring with a silver sunburst middle section, the dial is furnished with applied Roman numeral hour makers and small inverted triangles at the cardinal points. Additionally, despite the rather comprehensive calendar functionality of its movement, the dial of the new Duobox Triple Calendar Moonphase remains fairly clean and well-organized. A trio of sub-dials is arranged in a 6-9-12 formation, while two apertures for the day and month are placed within the register at 12 o’clock, and a calendar track for the pointer date is printed along the periphery of the dial.

In addition to its moonphase display and trio of calendar complications, the new limited-edition Brellum Duobox Triple Calendar Moonphase Chronometer also features a 12-hour chronograph, along with a 24-hour display of the time that serves as a day/night indicator. Set within the sub-dial at 12 o’clock is a small black-finished hand that tracks elapsed minutes for the chronograph, while another identical hand is mounted on top of the moonphase display and serves as the hours totalizer. The third register at 9 o’clock has two hands stacked on top of each other, and while the longer black-finished hand functions as the running seconds for the time, the shorter polished hand is linked to the two central time-telling hands, and it serves as the day/night indicator.

The majority of the hands on the new limited-edition Brellum Duobox Triple Calendar Moonphase Chronometer are either polished or finished black; however, the centrally-mounted chronograph seconds hand is dark blue to match the star-filled sky on the moonphase disc. Strips of Super-LumiNova are set within the central hour and minute hands, while two small luminous dots are placed on either side of the inverted triangle at 12 o’clock to help provide an orientation of the time when viewed in the dark. The day/night indicator also features luminous markings that are printed in white Super-LumiNova against the white-finished surface of the sub-dial, although they reveal sun rays and a crescent moon when illuminated, and the luminous material that appears on both the dial and hands emits a blue-colored glow in the dark.

Powering the Brellum Duobox Triple Calendar Moonphase is the brand’s Caliber BR-751 automatic movement, which is based on the core architecture of the Valjoux 7751. Similar to the ETA/Valjoux caliber that serves as its foundation, the Brellum Cal. BR-751 runs at a frequency of 28,800vph (4 Hz) with a power reserve of approximately 46 hours. However, because the Cal. BR-751 is a COSC-certified chronometer, it offers superior timekeeping compared to the standard version of this familiar base movement, and the Duobox Triple Calendar Moonphase is guaranteed to run within the tolerances of -4/+6 seconds per day. Decoration on the Caliber BR-751 is also a step above what you get from a standard Valjoux 7751, and it features blued screws with perlage and Geneva stripes on the bridges, plus a rose gold-finished rotor that is adorned with a realistic etching of the moon and each watch’s individual limited-edition number out of 46 total examples.

Fitted to the lugs of the new Brellum Duobox Triple Calendar Moonphase Chronometer is a black alligator leather strap that tapers from 22mm at the case down to 20mm where it connects to its signed stainless steel deployant buckle. Unlike some of Brellum’s straps that feature fitted end-pieces to form an integrated appearance with the case (such as the fabric strap fitted to the Pandial LE.5 DD DLC Full Black), the black alligator leather strap offers a more traditional design with slightly curved ends and integrated quick-release springbars to facilitate tool-free strap changes. The small gap that exists between the strap and the middle case provides the Duobox Triple Calendar Moonphase with a more traditional overall appearance, while the brushed and polished push-button deployant clasp is identical to what can be found on watches such as the Pilot LE.2 GMT Chronometer.

Despite being the most feature-packed model in Brellum’s current lineup, the new Duobox Triple Calendar Moonphase Chronometer is only slightly more expensive than its siblings, and its pricing ultimately seems quite fair considering its multiple complications and the general level of attention to detail that exists throughout the watch. For those of us outside the EU who do not need to pay VAT, the new Brellum Duobox Triple Calendar Moonphase LE Chronometer is priced at CHF 3,413.50 (or approximately $3,780 USD, at the time of writing). While this is still a considerable sum of money to spend on a watch, it also feels quite reasonable when you compare the Brellum Duobox Triple Calendar Moonphase to similar options within the industry, and I could easily see this same watch selling for a significantly higher price if it were produced by any of the big-name Swiss luxury brands. For more information on the Brellum Duobox Triple Calendar Moonphase Chronometer, please visit the brand’s website.