This thermometer is designed to measure body temperature in three ways - orally, rectally or under the arm (axillary). It will provide you with an accurate oral or rectal reading in just 5 seconds and an axillary reading in 20 seconds. Now you can take your baby's temperature in just five seconds orally or rectally, or in 20 seconds under the arm. When your baby is sick and fussing, the last thing you want to do is disturb her. Besides our 1-second ear thermometer, this is the fastest thermometer available.