These subs are quiet, diesel-powered boats with an excellent submerged sea and some kind of re-breather system that allows them to remain submerged for long periods. They have six torpedo tubes, and four larger tubes for assorted other weaponry.
These larger tubes can launch cruise missiles, conventional or nuclear. Actual location is, of course, classified. But the IDF probably keeps one at sea in the eastern Mediterranean, and another in the North Arabian Sea. 
The navy’s figures mark a rare revelation on the part of the IDF that suggests the military has significantly upped its operational presence to counter threats from Hezbollah and the more distant Iran.
https://www.timesofisrael.com/idf-sees-steep-rise-in-submarine-operations/
