The French born and Swiss made manufacturer has prepared its unique timepiece which will be offered at the Only Watch charity auction on the 7 November 2015, in Geneve to support scientific and medical research on Duchenne muscular dystrophy.
L. Leroy Chronomètre Observatoire Unique Piece for Only Watch is powered with the caliber L200 which incorporates the fundamental principles of horological science inspired by the work of Pierre Le Roy (1717 – 1785), “the father of modern chronometry” and the son of a famous watchmaker, Julien Le Roy, known for his absolute quest for accuracy and the man behind the extraordinary Leroy adventure.
The mechanism is built on 38 jewels and 4 jewels in diamond and it is capable to store enough energy to keep the watch working no less than 98 hours. The watch has oscillating rate of 18,000 alternations per hour (2.5 Hz). The stunning mechanism features the main-plate and bridges crafted from aluminiun which are entirely hand-finished.

Leroy Chronomètre Observatoire Calibre L200
This exquisite timepiece is a part of the Osmior line that is inspired by one of the historical models in the brand museum: an aluminium travel clock with grande sonnerie dating from 1894. Each timepiece from this line has been tested and approved by the Besançon Observatory, and comes with an individually numbered chronometer rating certificate.

Historical Aluminium Travel Clock
This one-off edition of the “Chronomètre Observatoire” was designed and developed so as to use aluminum as the material for the case, the dial, and as I have already mentioned for the bridges and the plate, thus paying homage to the Leroy’s amazing historical heritage, whilst incorporating a modern vision.
L. Leroy Chronomètre Observatoire for Only Watch is housed in a round case which measures 40mm in diameter and 10.50mm in thickness. The case is crafted from an aluminum alloy that has been treated to make it even harder and more resistant to external influences. The water resistance of the watch is assured down to 30 meters (about 100 feet). The case incorporates a circular satin-brushed bezel that features polished gadroons, and the polished rear bezel which is engraved with the inscription “Pièce unique” and “ONLY WATCH 2015”.
The watch’s case is protected on both sides with glare-proofed sapphire crystals. Under the front sapphire glass lies an aluminium dial which has a two-tone silver coloring, and is surrounded by a rail track minute index. The hour indexes are applied Arabic numerals, except at the 6 o’clock position where the second counter is placed. On the opposite side, just below the 12 o’clock numeral there is the brand’s logo applied.
At 12, 3 and 6 are small applied indexes which are situated between the rail track and filled with a luminescent material. The little red rhombus-shaped aperture is situated next to the 9 o’clock numeral and it reveals the power reserve indicator. From 0 to 60 hours, the disc remains the same colour as the dial, while from 60 to 80 hours, it switches to white, and beyond 80 hours appears in red to signal that the autonomy is nearly depleted. The dial also features steel and rhodiumed hands which are likewise filled with a luminescent substance.
This piece unique comes with a hand-sewn alcantara lined alligator leather strap, ending with an aluminium pin buckle.