Grey is the dial in the 37 mm Royal Oak line that stays in steel. It appears on the plain steel reference and on this diamond-set steel reference, and it appears in no gold configuration at either level of setting and in no gem-set version at all. That confinement is consistent with what the colour does: grey against a steel case and white gold markers is the most monochrome combination the size offers, and moving it into rose gold would introduce exactly the warm element the dial is chosen to avoid. Among the three steel dials in the diamond-set tier it is also the one that changes least with the light, since light blue brightens and Bleu nuit nuage 50 deepens while grey holds its position. Setting a bezel with diamonds over a dial that behaves that steadily produces a clear division of labour, with the stones supplying all of the movement and the dial supplying none.
The case is 37 mm across and 9.1 mm thick in stainless steel, with the octagonal bezel set with diamonds. That height is the same as the plain 37 mm reference of the same generation carries, because the bezel stones occupy metal that already existed, where the fully gem-set version of the same case reaches 10 mm since its dial and bracelet require channels cut throughout. The eight hexagonal screw positions survive the setting and the run of stones is built around them. The dial is grey with the Grande Tapisserie pattern, the larger of the two grids the collection uses. On a mid-tone ground the tapisserie reads with more definition than on either a dark or a pale dial, because the recesses have somewhere to fall and the brushed tops have enough light to hold, so the grid is visible at a greater distance here than on most of the collection. White gold applied hour-markers and Royal Oak hands sit above it. The bracelet is integrated steel, tapering from the case with the alternating brushed and polished treatment that identifies the model, and closes on an AP folding clasp. Everything on the watch is a neutral: grey dial, steel case, white gold markers, white stones. There is no colour anywhere on it, and the only variation across the whole watch comes from how differently brushed steel, polished steel, cut tapisserie and faceted stone handle the same light.
The function set is hours, minutes, centre seconds and a date. That is one function more than the fully gem-set references in this size carry, since those drop the date rather than cut an aperture through a continuous stone dial. Here the dial is metal and the window costs nothing, so the reference retains the complication the collection has fitted since 1972. Centre seconds keeps all three hands on one axis. The applied markers give fixed points to read against, and against a mid-grey field with white gold hands the contrast is moderate rather than strong, which is the one legibility cost of a fully neutral dial. The bezel setting sits outside the dial entirely and affects none of it.
The Royal Oak is the collection Audemars Piguet is built on, and the 37 mm anniversary references step through three degrees of setting. The plain reference is unset at 9.1 mm, this reference sets the bezel and leaves the dial alone at the same height, and the fully gem-set reference sets dial, bezel and bracelet in one coloured stone and reaches 10 mm. Within the diamond-set tier the steel references run light blue, Bleu nuit nuage 50 and grey; the rose gold references run silver-toned, Bleu nuit nuage 50 and khaki green. Bleu nuit nuage 50 is the only dial appearing in both metals. Each of the six anniversary references is matched by a standard-catalogue counterpart carrying the same dial without the anniversary designation, and a white gold version of the case takes a different approach again with baguette-cut diamond hour-markers.
This reference suits a collector who wants a set bezel without any of the associations that usually come with one. Grey on steel with white stones is a fully achromatic watch, and it reads as a piece of hardware that happens to be set rather than as jewellery. That is a specific and fairly rare thing to want. It appeals to someone who finds the coloured dials too declarative and the gold references too warm, and who values the fact that this dial holds its appearance through the day rather than shifting with the light. Grey also carries no seasonal or occasional association in the way that green, light blue or a deep anniversary navy inevitably do, which makes it the least situational dial in the size. Keeping the date and the applied markers also makes it more usable than the fully gem-set references at the same size, which trade both away. The anniversary designation ties production to the occasion rather than to an open catalogue run.
