features stealth technology to minimize the radar signature of a ship. Anti-submarine warfare The ships carry the RPK-8 system, which uses a 12 barreled RBU-6000 ASW rocket launcher to fire the 212 mm 90R anti-submarine rocket or RGB-60 depth charges. The firing range is from , and the depth of engagement is up to . Two twin 533 mm DTA-53-11356 fixed torpedo tube launchers are fitted amidships and fire the SET-65E/53-65KE torpedoes. The Purga anti-submarine fire-control system provides control for both the RBU-6000 and DTA-53 launchers. Electronics and sensors Radar Surface search: One 3Ts-25E Garpun-B radar at I-band frequency, using both active and passive channels, provides long-range surface target designation. One MR-212/201-1 radar at I-band frequency is used for navigation and a separate Kelvin Hughes Nucleus-2 6000A radar set is used for short-range navigation and surface surveillance. Also fitted with a Ladoga-ME-11356 inertial navigation and stabilisation suite supplied by Elektropribor. Air/surface search: One Fregat M2EM (NATO: Top Plate) 3D circular scan radar at E-band frequency, provides target indication to the Shtil-1 missile system. Featuring continuous electronically scanned arrays, the radar rotates at 12 or 6 rpm and has an instrumented range to 300 km. Fire control: Features a Ratep JSC 5P-10E Puma fire control system, consisting of a phased array and target tracking radar along with laser and TV devices. The system, fitted above the bridge deck, features in-flight course correction updates via data links, has a maximum detection range of 60 km, operates autonomously and is capable of automatically locking on to four targets and tracking them. Sonar According to some reports, the APSOH (Advanced Panoramic Sonar Hull) hull-mounted sonar is fitted on the vessels. The APSOH sonar performs active ranging, passive listening, auto tracking of targets and classification. Other reports indicate that the BEL HUMSA (Hull Mounted Sonar Array) sonar is fitted. The HUMSA is a panoramic medium-range active/passive sonar system developed by the Naval Physical and Oceanographic Laboratory (NPOL). As a stop gap measure, Russian Bronza (MG-345) hull mounted sonars are installed. Information released from the Severnoye Design Bureau (SDB) indicate that French towed array sonars (TAS) are also fitted. This is very plausible given that many Indian Navy ships now use French TAS, however INS Talwar shows no signs of such a system. The vessel may also have a Russian SSN-137 Variable Depth Sonar (VDS) with NATO reporting name Steer Hide, providing active search with medium