Correct. They use other liquids.
They have this one in stock at the Walgreens near me. And it’s made in Germany. I think I’m going to get one.
https://www.walgreens.com/store/c/geratherm-mercury-free-oral-thermometer/ID=prod396857-product
I have one of those German-made Geratherm thermometers. They're very uncomfortable to keep in your mouth, as they have a large diameter.