The Bavar-373 surface-to-air missile system (also known as Belief-373) has been improved, according to the Iranian IRNA news agency, and now has a range of more than 300 kilometres.

Mohammadreza Ashtiani, the Iranian defence minister, was present for the announcement event. A long-range missile named Sayyad B4 was launched at the ceremony to successfully test the Bavar-373 system (Hunter B4).
During testing, the Bavar-373 surface-to-air missile system’s enhanced radar was able to identify targets at a distance of over 450 km, track them at a distance of 405 km, and then destroy them at a distance. more than 300 kilometres. Prior to the modification, the Bavar-373 system could locate, track, and strike targets at distances of 350 km, 260 km, and 200 km, respectively.
On August 22, 2019, the Bavar-373 system was formally introduced for the first time.
A production line for the Sayyad B4 rocket powered by mixed solid fuel was also established alongside the Bavar-373 system’s launch ceremony.