Mabis Healthcare Inc. manufactures a small thermometer that is a good alternative to the glass thermometers. It's called the "Tiny Temp Digital Miniature Thermometer", but honestly, it looks like a regular sized thermometer to me!
I bought this to use on my grandson, but occasionally I have to take my own temperature. To turn it on, I press a blue button located at the opposite end of the part that goes under the tongue. A letter "L" appears on the display screen, with a flashing letter "F" in the corner. I place the tip under my tongue and wait until the flashing "F" stays steady. The problem is, there is no indication when it reaches the final temperature other than when the "F" stops flashing in the display screen! No beep; no anything! So if I take my own temperature, I have to glance at the display screen through a mirror to see what's going on! Otherwise it's fine if you take someone else's temperature.
The thermometer seems pretty accurate, however I wouldn't have any way to gauge it if it wasn't. The results usually take about 60 seconds, but since the display screen is small, it can be difficult to read. Isopropyl alcohol is used to clean the tip, or you can use cold soapy water to wipe it down.
The casing is made of plastic, and the thermometer is mercury-free and waterproof. There is no way to replace the battery when it 'dies', so once the display gives an error message, it's time to throw it away.
It's a good, cheap, thermometer that will do in a pinch. I suppose if you had more serious health issues, with a need to monitor a fever, you'd want something better than this.