Air Freshener Jars

[Guest guest]

Maybe someone here can help me.

I was in a shop where you have things made for you, shampoos etc..and

the lady makes air freshener jars.

She puts in scented oil, color and then beads to about 1/4 full in the

jar. Then she adds water, the beads swell up and she puts a lid on

with holes for the scent to permiate through the room...

What are the beads? I want to make it. I use Essential oils alot and

want to make my own for gifts.