How do those videos of pure tones in the sub 1Hz or in general any Hz tones produce that tone for the video?

I want to be able to do that too, like this one for instance

PURE 0.33 Hz EPSILON BINAURAL BEATS | Epsilon Waves | Reality Shifting ⚡️

It would be great to be able to produce any arbitrary Hz pure tone or whatever that example is

Like 0.165Hz or anything