Tuning fork with stylus 02, with variable frequency

To visualize and record vibrations;
large-scaled model of a tuning fork including a holder for pencils,
clamping weights to change or adjust the frequency, with handle,
delivered with a pencil,
Frequency: approx. 2.4 – 4 Hz

* ) clean recording of damped vibrations on a sheet of paper
* ) the frequency can be changed by moving the clamping weights