As long as i make sure to keep the bubbles horizontal to the fretboard it plays fine and makes a nice crisp sound

It does give a nice bluesy sound

Nice smooth sound.

Thick slide sound that is less shrill and very warm sounding

Soft, pleasant sound.

Like the sound of a glass slide compared to a metal one.

I like the sound of a glass bottle more than a butter knife but there may be more uses for a

Not great sound.