Shop thermometers here at Med-Vet International. Find forehead, digital, ear, oral, and rectal thermometers. The more accurate type of thermometers are digital thermometers. These consist of a probe and contains a sensor at the end. The probe touches part of the body and reads the body's temperature. The three type of digital are usually oral, rectal, and axillary. These are the most common type of thermometers. An oral thermometer is placed under the tongue and a rectal thermometer is placed in the rectum. These typically get a reading in a minute or less. An infrared ear thermometer measures the temperature inside the ear. Ear thermometers tend to be more expensive. If there is too much was inside the ear, the thermometer may not give an accurate reading. Forehead thermometers are not as reliable as digital ones. They are placed on the temporal artery of the forehead and read the infrared heat.