The Jaeger-LeCoultre Master Mariner "Deep Sea" is one of the timepieces that have slipped under the radar being overshadowed by other dive watches from the respective era. Launched in the late 1960s, the Jaeger-LeCoultre Master Mariner was certainly a cool timepiece with a very distinctive appeal equipped with a supercompressor case with double crowns and an inner rotating bezel. Developed as a professional tool watch for diving, the two piece case is composed of a screwed down caseback secured with a rubber gasket enhancing its waterproof capabilities.