Turning its gaze back to the past, Tudor presents a new Pelagos in a left-handed version, with the winding crown therefore positioned on the left side of the case middle, so that it can be worn comfortably on the right wrist. Tudor had already produced watches of this type at the request of diving professionals, for example for the French Navy. Diving watches designed to be worn on the right wrist must have special ergonomic features. Before the advent of this watch, left-handed divers wore their watches on their right wrist and backwards. In this way they could only use the elapsed minutes function, but their dominant hand was free to access the winding crown. With the introduction of this new model in the Pelagos line, named LHD (an acronym for "Left Hand Drive", or left-handed winding), Tudort is now able to offer a complete line of dive-watches while revealing a little-known part of the brand's product development history. In keeping with the best watchmaking tradition of assigning specific reference numbers to instrument watches, the Pelagos LHD is produced in a numbered series. Each piece has a unique production number engraved in Arabic numerals clearly visible on the case back. This is a first for Tudor. The dial of this new Pelagos model, moreover, has been reworked with graduations in beige luminescent material and with the name "Pelagos" written in red at 6 o'clock. The date window, also in beige, has a new design with the numbers written in alternating colours: even days in red and odd days in black. This aesthetic detail, nicknamed "roulette" by collectors, was a characteristic feature of Tudor dive watches along with the "snowflake" dial and hands first used in the Reference 7021 in 1969. In the same style, the unidirectional rotating ceramic bezel has graduations in beige luminescent material that echo those on the dial. This is a variant of the movement produced by Tudor developed specifically for the new left-handed version of the Pelagos. The Pelagos is also distinguished by its titanium bracelet, which is equipped with a steel folding clasp with a self-adjusting spring mechanism, developed and patented by Tudor. Thanks to this ingenious system, the bracelet adjusts during the dive, contracting when the wetsuit is compressed to great depths and expanding when the pressure decreases during ascent. The Pelagos also comes with an additional rubber strap with an extension system that makes it easily adjustable for every type of dive. The water resistance of the Pelagos LHD is guaranteed up to 500 metres and has been systematically tested up to 125% of its capacity, i.e. up to 625 metres. Also noteworthy is the presence of the automatic helium escape valve, an essential device for preserving the watch during saturation dives. In this diving technique, divers' bodies are saturated with a mixture of helium and oxygen, allowing them to alternate periods of underwater activity with periods of rest in the hyperbaric chamber so as to avoid long decompression phases during the dive. Since the helium atom is the smallest gaseous particle in nature, it manages to penetrate the inside of the watch after a certain amount of time, no matter how waterproof it may be. The automatic helium escape valve allows the gas to be expelled from the watch during the decompression phase (which is much shorter than diving), without damaging it. Without this system, the excessive pressure caused by the large number of helium atoms present would cause the watch to explode during the decompression phase.