The US-350 airspeed indicator is designed to determine the airspeed of a helicopter. 

The device operates by measuring the difference between the dynamic and static air pressure in flight. 

The sensitive element of the device is a pressure gauge box. The device has an airspeed measurement range from 0 to 350 km/h. The division value is 10 km/h. 

Each airspeed indicator is supplied with correction charts, which are fixed on special cassettes located on the glazing profiles of the pilot's cabin.The US-350 speed indicator is installed on airplanes, helicopters and gliders with a low flight speed.