9A4172 Vikhr (, ) (NATO reporting name: AT-16 Scallion) is a Russian laser guided anti-tank missile system. "9K121" is the GRAU designation for this system. The missile is air-launched from the Ka-50, Ka-52 helicopters and Su-25T aircraft. It is believed to have entered service around 1990, having been first shown publicly at the 1992 Farnborough Airshow.