Longines HydroConquest watches

The Longines HydroConquest is the brand's sports dive watch, introduced in 2007. Longines rates it to up to 300 m and gives it a unidirectional bezel, a screw-in crown and a screw-down caseback, with a pair of guards either side of the crown. It comes with either an automatic or a quartz movement, depending on the model.

The 41 mm L3.642, from before the 2018 update, has an aluminium bezel insert with a luminous pearl at 60 and Longines calibre L633, based on the ETA 2824, with a 38-hour power reserve. In 2018 Longines reworked the line with new dial colours and matching ceramic bezels; the 41 and 43 mm automatics of that update, such as the L3.782, run on calibre L888.2, ETA's A31.L01, with about 64 hours of reserve. Longines' current automatics use a silicon balance spring.

The quartz models run from 25 mm and 29.5 mm watches, several with mother-of-pearl dials and diamonds, up to a 47.5 mm chronograph. The automatics are mostly 39, 41 and 43 mm, with a 30 mm automatic at one end and a 44 mm at the other, and automatic chronographs in the 41 and 43 mm cases. Two-tone versions add yellow or rose gold to the steel.

A few variants stand apart. The 43 mm HydroConquest Ceramic (L3.784.4.56.9) has a black ceramic case rather than steel. The PVD-coated 41 mm automatic L3.742.2.56.6, a Japan edition, is limited to 500 pieces. The L3.781.4.59.6 is a 41 mm automatic named for the XXII Commonwealth Games.