The Santos Skeleton ADLC "Noctambule," which is French for "night owl," was unquestionably one of the coolest addition to Cartier's Santos line after the collection was totally revamped in 2018. Amorphous diamond-like carbon (ADLC), a hard coating derived from diamond that boosts the case's scratch-resistance, has been applied to the stainless steel case. The surface is a dark, dark grey rather than pure black, which is typical of an ADLC coating and complements the movement's silvery-grey hues. Skeleton watches are a hallmark of Cartier, especially when the base plate and bridges have been open-worked to create Roman numerals and sword-shaped hands—two characteristics that define a Cartier watch. The "Noctambule" expands on the concept by giving the skeletonised movement a Super-Luminova coating that glows in the dark for several hours after being "charged" with light; both artificial and natural light can accomplish this. Currently it’s the largest size Santos case, measuring 39.8mm wide and 47.5mm lug-to-lug, which makes it seem, at least on paper, like a very large watch. But the case is relatively slim, just 9.8mm, high, while also being curved, so it sits well on the wrist. A standout unisex piece with a daring presence. The present watch comes fitted on it's original grey alligator strap and also comes with a second black alligator strap.