Well, it does what it does. For whatever use that is. Back in the day, I'd generate sounds of a given frequency using GWBASIC using the sound command, and it went up to 32767 Hz. But you can only get so much out of a computer's speaker. Which is why once I used a big 2 inch piezo disc designed for use as a high frequency transducer, with a high voltage signal generator I made to make a 23 kHz sine wave. It was loud enough that even I could hear it, at that frequency. I turned it on near a cat, which then hissed at me. But I don't really know how annoying it was, the cat hated me anyway so it might have hissed either way. As for the neighbor's dog when it starts abarkin' at 2 in the mornin', a bloody sound weapon is not good for long range, for that I need to shine a laser pointer in its eyes. To me now, this just reminds me of the damage I have received from being run over by a car, since my left ear is deaf, and constantly generating the phantom noise of nails on a chalkboard, and my right ear can easily hear 18 kHz, although it's almost swamped out by the phantom noise I'm hearing on the left.
You know, really, rather than a choice you pick from among 5 buttons, there should be a field where you just enter in the frequency in Hz. that you want. So if you want 20 kHz, you enter in 20000.