The Project 636.3 Kilo-class is an improved variant of the original Project 877 Kilo-class design. The updated version is slightly longer in length — the sub’s submerged displacement is around 4,000 tons — and feature improved engines, an improved combat system, as well as new noise reduction technology. The submarine has a crew of around 50 and can conduct patrols for up to 45 days. The improved Kilo-class can fire both torpedoes and cruise missiles, launched from one of six 533 millimeter torpedo tubes.
SOURCE- Tass, The Diplomat