PM-525 WIND VANE

For meteorological departments and for mounting on buildings for
accurate indication of wind direction. Consist of a central pillar
mounted on a 25 mm. diameter pole and carries four arms
terminating in cardinal point symbols. Height 300 mm., with round
base and diameter of central rod 10 mm. Well balanced to avoid
bias towards any particular direction, produces maximum torque
relative to its moment of inertia for a given change in wind
directions it rotates with the minimum of friction.