Calibers

Prokop & Brož is currently one of the companies that expand their design and manufacturing capabilities in the production of in-house calibers year after year.

What began in 2012 with the development and production of special add-on modules enabling alternative ways of displaying time very soon grew into in-house production of the key components that most influence the appearance of a caliber. The reason was the need to support functional originality with an unmistakable appearance as well, when viewed through the sapphire crystal of the caseback. Incidentally, display casebacks are standard on all Prokop & Brož watches unless the customer requests otherwise.

In 2024 and 2025, Prokop & Brož took another step toward complete independence. The company completed the development and full design of a new caliber, designated PB120, which differs from all the others in having an off-center, directly driven seconds hand at the 12 o’clock position.

Among the first expressions of the company's own invention in the field of calibers were therefore modules. However, as the young company's manufacturing capabilities grew, its creativity began to show in the design of all the bridges and plates as well. From simple manual and CNC skeletonization to in-house production of these parts, the company soon reached the point where it could compose its calibers as an integral part of the overall watch design.

As early as 2013, it introduced its fully skeletonized caliber PB30 with central seconds and a different method of locking the mainspring barrel, a screw-balanced oscillator and swan-neck fine regulation.

The original bridges with slender arms were designed to reveal as much as possible of the individual wheels and the points where they engage. The setting of the necessary jewels was also handled with care. Everything is complemented by originally skeletonized winding wheels and screws of various sizes with heads of the company's own design, so the result is, in its way, a work of art.

As mentioned in the introduction, the high point of the in-house production so far is the PB120 caliber, which the company designed itself. With it, the company wanted to pay tribute to the first chronometers, which had an off-center seconds hand at the 12 o’clock position.

A collaboration with the carmaker Škoda Auto played an important role in launching series production of this caliber. The result was a joint watch project celebrating the 130th anniversary of the founding of Laurin & Klement, the direct predecessor of the Mladá Boleslav carmaker.

The limited series of 30 gold and 100 stainless steel watches both made possible and demanded an optimization of the production process. This led to considerably greater precision in the manufacture and subsequent finishing of all components, and to more efficient assembly of the new calibers.

In 2012, the year it was founded, Prokop & Brož began building its watches on the proven ETA/Unitas 6497 and 6498 calibers. Very soon, however, there was also a need for movements with automatic winding. The choice fell on the ETA 2892-A2 caliber.

It is only fair to admit that although the company designates these calibers with its own codes, their basic construction remains unchanged. The most significant modifications are visually attractive surface decorations and contrasting electroplating or anodizing. The only newly manufactured parts are rotors in two sizes for differently designed watch cases. These calibers are thus unique above all in their design.