I've used it a few times, but I'm selling it because I no longer need it. I only used it in my armpit. It's a measured-temperature type, so it takes about 3 minutes from the start of measurement until it beeps. The following is an excerpt from the Omron electronic thermometer description: Standard type with a notification buzzer. Measured-temperature type <armpit/mouth> Flat sensor that doesn't easily slip out of place in the armpit or mouth Omron's unique flat sensor, with a flat tip, is used for the temperature-sensing part. Because it fits snugly under the arm or tongue, it's easier for even small children to keep the thermometer in place until the measurement is complete. A buzzer sounds when the measurement is complete. (The buzzer sounds when the temperature rise slows down and approaches equilibrium. *) * For accurate measurement, it takes about 10 minutes in the armpit and about 5 minutes in the mouth.