Monochrome Watches
An online magazine dedicated to fine watches

Jaeger-LeCoultre Master Ultra Thin Moon and Master Eight Days Perpetual 40

| By Frank Geelen | 3 min read |

Jaeger-LeCoultre has had a very busy year with many new releases. Earlier they released three new models in the Master Control collection and I didn’t have time to share these with you: the Master Ultra Thin Moon and the Master Eight Days Perpetual 40. 

At the time Jaeger-LeCoultre officially launched three new models of the Master Control collection, we shared an extensive review of the new Master Geographic with you. We’re still very exited about the new, slightly smaller, dimensions and superb attention for detail. Now it’s time to take a look at the Master Ultra Thin Moon and the Master Eight Days Perpetual 40.

The new Master Ultra Thin Moon is a sophisticated and classy dress watch, featuring a moon phase and an ultra-thin movement with automatic winding. The movement, caliber 925, is only 4.9 mm thick and indicates hours, minutes, seconds, moon phase and the date. This in-house developed and manufactured movement comprises of 246 parts, of which 30 jewels, and delivers 43 hours of power reserve when fully wound.

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The case measures 39 mm in diameter and is only 9.9 mm thick and is available in either stainless steel (with silver dial) and pink gold. It looks like the same pink gold as that used on the Master Geographic, which is absolutely gorgeous. On the dial we see the alpha shaped hour and minute hands, a central second hand and the moon phase and date are displayed in one sub-dial positioned at 6 o’clock.

The other novelty this year is the Master Eight Days Perpetual 40: an exceptional 8-day power reserve. In 2004 Jaeger-LeCoultre introduced their first manually-wound 8 Days Perpetual Calendar, which was followed by skeletonized versions in 2007 (platinum, limited to 100 pieces) and 2008 (rose gold, limited to 175 pieces). This year JLC introduces a new version with the same excellent features, in a 1.5 mm smaller case that now measures 40 mm.

For a collector, owning several timepieces, it’s very handy that a perpetual calendar has a long power reserve. The movement, caliber 867, has to barrels providing the energy. When you don’t wear a perpetual calendar, with around 40 hours of power reserve, for a few days you will have to set the time and the calendar again. This Jaeger-LeCoultre can be put in the vault for a week and will still indicate the correct time, date and moon phase.

Another great feature is the night and day indicator (positioned at 1 o’clock), with a small aperture that turns red, to remind that the date must not be set between 10 PM to 3 AM, as to avoid any damage to the movement. Another great point, is that you set all calendar data by using just one pusher.

On the dial we see the day and night indicator, the date (at 3 o’clock), the month (at 6 o’clock), the year in four digits (between 7 and 8 o’clock), the moon phase and day of the week (at 9 o’clock) and at 11 o’clock the power reserve indicator.

Like all watches from the Master Control collection, these two watches are tried and tested on precision and reliability for 1,000 hours, before they are delivered to the client.

More information can be found at the Jaeger-LeCoultre website and the official Facebook page.

1 response

  1. The Master Eight Days Perpetual 40 is truly stunning ! The fact that the power reserve is so long for such a complicated watch is outstanding !


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