An impeller nebulizer uses a screen and small vibratory motor to dispense the neb solution directly into a mouthpiece. The mesh screen breaks up the liquid into tiny droplets which you inhale.

The only one I have use is the Philips Innospire Go, which is rechargeable and comes apart for cleaning. (https://www.usa.philips.com/c-e/hs/respiratory-care/innospire-go.html) This is not an endorsement, but the site does give an idea how these work. It has been in short supply, so I don't know if it is available now. Others may be able to recommend different brands.

Sue

Like Sue, I have used, and loved, the Innospire Go. Mine stopped charging just as their supply chain shut down and I had to find an alternative.
I’ve been using the Microair U100 by Omron. It’s another mesh nebulizer like the Innospire Go.
I’ve been very happy with it. The specs on particle size are the same as the Innospire, and subjectively to me it works just as well and is just as quiet. It’s less expensive, can be powered with a plug or AA batteries, and can be boiled to sterilize (not microwaved!!). You can order a replacement for the mesh part for just $35 if it gets damaged somehow or slows down due to mineral deposits.
I still prefer the simplicity of the Innospire Go, but the Omron is a great substitute, especially for travel.