In the United States Navy naming system, and in the equivalent NATO system (STANAG 1166), nuclear-powered attack submarines are known as SSNs and their diesel-electric predecessors were SSKs.
Di sistem penamaan Angkatan Laut Amerika Serikat, dan dalam sistem NATO yang setara (STANAG 1166), kapal selam bertenaga nuklir dikenal sebagai SSN dan pendahulunya diesel-electric adalah SSK.