Joining the recently announced sapphire dial perpetual calendar, Montblanc has added two decidedly modern interpretations of the Exo Tourbillon Slim to the Heritage Chronométrie line of classically styled, dressy watches.

Launched in 2010 as a top of the line product, the Exo Tourbillon is unique to Montblanc, and now much more affordable. Now starting the US$35,000 mark, the Heritage Chronométrie Exo Tourbillon still costs a chunk of change, but as tourbillon wristwatches in gold cases go, is relatively entry-level.

The watch gets its name from the fact that the balance wheel sits outside and above the tourbillon cage. A smaller cage requires less energy to rotate, boosting the efficiency of the movement, while the balance freeing the balance from the cage allows it to be larger and have more inertia, increasing timekeeping stability.

Both new models are equipped with the automatic cal. MB 29.24, a slim movement with a micro-rotor and hacking function, meaning the tourbillon stops when the crown is pulled to set the time. The pair are both in 18k white gold and feature the redesigned Heritage Chronométrie with slimmer lugs that’s 40mm in diameter and 8.9mm high.

The Heritage Chronométrie Exo Tourbillon Slim has a slate grey dial finished with vertical brushing, accented with a subtle blue chapter ring for the minute track. Arabic numerals mark the quarters, with baton markers filling up the hours in-between.

The movement features a newly designed, flat-polished tourbillon bridge with hexagonal ends that are secured to the based plate with blued screws. Partially visible in the top of the aperture for the tourbillon is the blued lever that stops the tourbillon by touching the balance wheel.

The Heritage Chronométrie Exo Tourbillon Slim (ref. 118471) is priced at €33,500, or S$47,100. That’s equivalent to about US$35,000.

The fancier iteration is the Heritage Chronométrie Exo Tourbillon Slim Openworked that’s also white gold. Again, the same colour scheme has been applied to the dial, which has a dark blue minute track and blued dauphine hands.

The watch is also equipped with the cal. MB 29.24, but here it’s been skeletonised in a modern, geometric style with alternating brushed and frosted surface finishing. Notably, even the gears and barrel are fabricated in the same style, resulting in straight, angular spokes.

The open-working was inspired by dazzle camouflage, the camouflage patterns painted on naval vessels, primarily during the First World War, that were intended to distort a ship’s direction, range and speed.

The Heritage Chronométrie Exo Tourbillon Slim Openworked (ref. 118512) is priced at €39,700, or S$55,800. That’s about US$41,000.