I use them and the noise they make is why some still refer to bite alarms as buzzers. There are no single bleeps, peeps, pips or any of that warbling that goes on with the Delkims. I'm sure the buzzer from the Heron's sounder box would be well at home in the servant quarters of a mansion house.
A vane anemometer thus combines a propeller and a tail on the same axis to obtain accurate and precise wind speed and direction measurements from the same instrument. The speed of the fan is measured by a rev counter and converted to a windspeed by an electronic chip.
An anemometer looks like a weather vane, but instead of measuring which direction the wind is blowing with pointers, it has four cups so that it can more accurately measure wind speed. Each cup is attached to the end of a horizontal arm, each of which is mounted on a central axis, like spokes on a wheel.