These boxes are constructed from hardwood and feature an A4 tuning fork mounted directly to the box. If tuned to the same frequency, striking one will cause the other to go into sympathetic vibration.
The demonstration tuning fork whose oscillation is so slow that the note cannot be heard (around 5.4 Hz). On the other hand, it is easy to follow its movements with the eyes.
Made of nickel-plated steel.
Length 78 cm