Same as reference 25820 but in an openwork version, reference 25829 was produced for the same period (1996-2013) and made in 371 pieces in steel, 102 pieces in yellow gold, 174 in pink gold, 156 in platinum, 25 in steel and platinum plus another one made in 2006, 15 pieces in tantalum and yellow gold, 16 in tantalum and platinum, and 16 in tantalum and pink gold.

While two tone cases made of contrasting metals (such as platinum and pink gold, or steel and yellow gold) are easily understood from an aesthetically point of view, two-tone cases made out of similar metals are much more subtle - but not in the least less impressive - creations. The aesthetic “ton-sur-ton” effect that stems from the gentle gleam of platinum meeting the darker, sterner, more military hue of tantalum, is absolutely captivating.

Its remarkable looks are just a part of the attractiveness of this piece, as they are couple with a very unusual production history which results in an even more restricted output than the number 25 on the caseback would suggest.

In fact, 25 such numbered cases were produced by Audemars Piguet (this being the last of the batch). However, they were employed - not with consecutive case range - on 2 different references: 16 examples were used for the present ref. 25829TP with openworked dial, and the rest on its sibling ref. 25820TP with solid dial. Thus this is a very quirky - and enormously collectible - example of a 16 pieces limited series model bearing number 25.

Given its looks and production history, it is unarguable that we are in the presence of a masterpiece that is as important and collectible as it is exquisite and entrancing.