Tasing? Not likely.
Look closer. There is no capacitor to store voltage.
All this is is an automotive type light bulb without the glass.

Notice that the section nearest the batteries looks like the base of a bulb?
All this does is heat up a filament like your car cigarette lighter. There is
even a picture of the red hot filament on the auction page.

You could certainly give someone a good burn though.

All the same, perhaps a useful addition to a PSK. I would certainly NOT
depend on it though...