These work very well.
I used one when I was treating a snake for RI. This helped to keep the mucous thin enough for her to breathe while the medicine did it's job. You can make them as small or as large as you need.
For a single snake in a quarantine tub, I used the smallest air pump I could find, and an empty 20 oz soda bottle. If you have multiple snakes and all the tubs need help, you can buy a big dual outlet air pump and use gallon jugs.
They don't make a lot of noise, and are safe as long as you clean the jugs at least once a week to prevent algae or bacteria buildup.
Gale