The Nag missile, also called "Prospina" for the land-attack version, is an Indian third-generation, all-weather, fire-and-forget, lock-on after launch, anti-tank guided missile (ATGM) with an operational range of 500 m to 20 km. It has a single-shot hit probability of 90% and a ten-year, maintenance-free shelf life. The Nag has five variants under development: a land version, for a mast-mounted system; the helicopter-launched Nag (HELINA) also known as Dhruvastra; a "man-portable" version (MPATGM); an air-launched version (which will replace the current imaging infra-red to millimetric-wave active radar homing seeker; and the Nag Missile Carrier "tank buster", which is a modified BMP-2 Infantry Fighting Vehicle produced under license in India by Ordnance Factory Medak.