ultrasonic pain inducer?

Ha! I wouldn't bet your life on it!

Don't these claims seem rather extraordinary for a device powered by a mere 9-volt battery?

The devices on that page probably do something, but probably not all that the marketing copy would have you believe.

For info on a real ultrasonic pain inducer, check out:

devices use the mixing of two ultrasonic beams to produce another acoustic signal at the absolute difference of the original frequencies. Besides inducing pain, other variations of the device can send "voices" and other sounds to people which seem to them to be originating inside their head.

A very helpful response. Thank you.