Improved Akula-I Hulls: K-328 Leopard, K-461 Volk, K-154 Tigr, K-419 Kuzbass, K-295 Samara and K-152 Nerpa. These submarines are much quieter than early Akula class submarines and all have the SOCKS hydrodynamic sensors except Leopard. The Akula-I Improved submarines have 6 533 mm decoy launching tubes, as do subsequent submarines. They have a different arrangement of limber holes on the outer hull than Akula Is. Nerpa and Iribis (not completed) have a different rescue chamber in the sail. I can be distinguished by the large dome on the top surface.