Brellum’s calendar chronograph looks good, but 15.2 mm is a lot

The blue dial and steel bracelet make a very convincing first impression on this Brellum. Then I get to the 15.2 mm thickness and start wishing I could take a few millimeters off it. I enjoy a complicated chronograph, and this one has a handsome arrangement, but the small diameter doesn't automatically make it a slim watch. My rating is 82 out of 120 bezel clicks.

This is the Duobox 39 TC Moonphase, reference DB.CH.952, in Night Blue. Brellum calls it a 39 mm case in its promotional copy and specifies 39.5 mm in the measurements. The production run is 46 numbered watches. This is a source-based first look, so the wrist photographs shown here are Brellum's material, not evidence that I've worn it.

The moon belongs at the bottom

I like the moonphase sitting in the lower counter. The day and month windows near the top give the dial a clear vertical arrangement, while the date travels around the outside. The Roman numerals make it feel more formal than a typical racing chronograph. On the blue background, the pale printing is easy to separate in the photographs.

There is still a lot to read. The extra hand, calendar track and smaller indications make the dial considerably busier than the kind of simple everyday watch I usually gravitate toward. Here I can follow the logic of the layout, and I like the overall appearance enough to keep looking. I would want to try reading it at ordinary wrist distance before deciding how well those details work together.

The bracelet's rounded links suit the case. I'd probably start there rather than choosing the leather immediately, although an actual fit check could change that. Brellum says the watch includes the bracelet and a choice of black or brown calf-leather strap. That gives you a second way to wear it without treating each strap choice as a separate model.

A familiar mechanical basis, with a thick case around it

The automatic BR751 is based on the Valjoux 7751 and carries COSC chronometer certification. Its stated reserve is 46 hours. The chronograph is joined by a complete day, date and month calendar, a day/night indication and the moonphase. Water resistance is 100 m, and the stated lug-to-lug length is 48 mm.

Those are useful specifications, but I would still want a side-on wrist check. A tall case with a raised crystal can feel quite different from what its diameter suggests. This could be a watch I enjoy looking down at and keep catching on a cuff.

The captured maker listing shows CHF3,890 including Swiss VAT. Outside Switzerland, Brellum says prices exclude Swiss VAT and payment is in francs. A verified USD quote and a confirmed US delivery date weren't established as of November 14. I'd settle those details before comparing the purchase price with another calendar chronograph.