Longines Watch HydroConquest. HydroConquest, profoundly sporty. Diving watches par excellence, the models in the HydroConquest series are a homage to the men who have dedicated themselves to conquering the oceans and to enthusiasts of the open seas. They meet the strict requirements demanded by this discipline: they are water resistant to 30 bar or 300 metres, are fitted with a unidirectional turning bezel, screw down case and screw in crown, lateral protection for the crown and double security folding clasp with integrated diving extension piece. These rigorous guarantees of uncompromising safety fit in perfectly with the harmony of this silent world. Performance and elegance, a unique Longines combination.