> ## Documentation Index > Fetch the complete documentation index at: https://docs.sonohealth.com/llms.txt > Use this file to discover all available pages before exploring further. # How No-Touch Infrared Thermometers Work > How infrared and no-touch forehead thermometers measure temperature, why they're convenient for babies, and how to get the most accurate reading. No-touch and forehead infrared thermometers have become a household staple because they're fast and don't disturb the person being checked. Knowing how they work helps you use them accurately. SonoHealth's **ThermoPRO** and **ThermoMax** are infrared thermometers for quick home readings. A thermometer measures temperature; for what counts as a fever and when to act, see the [fever guide](/thermometer/fever-guide). ## How does an infrared thermometer measure temperature? Everything warm gives off infrared energy. An infrared thermometer reads the heat radiating from the skin (usually the forehead) or, in some models, the eardrum, and converts it into a temperature in a second or two — no contact or only a light touch required. ## Why are they popular for babies and kids? Speed and comfort. A [no-touch forehead scan](/thermometer/how-to-take-accurate-temperature) lets you check a sleeping baby without waking them, and there's no probe to hold in place on a wriggly toddler. That convenience makes frequent checks during an illness much easier. ## How do I get an accurate reading? * Make sure the **forehead is clean, dry, and uncovered** — sweat or hair skews results. * Avoid measuring right after the person has been **bundled in blankets** or **outside in the cold**. * Hold the device at the **distance the manual specifies** and aim at the center of the forehead. * Let the person settle for a few minutes if they've been active. ## Why do my readings differ between devices or spots? Infrared readings can vary with technique, skin temperature, and the exact spot measured, so two devices may differ slightly. For tracking an illness, use the **same thermometer and method** each time and watch the trend rather than chasing exact numbers. Compare methods in our [forehead vs ear vs oral guide](/thermometer/forehead-vs-ear-vs-oral). ## Care and storage Wipe the sensor gently per the instructions, keep it at a stable room temperature before use, and store it away from moisture and extreme heat or cold so it reads accurately. *** **Related:** [How to Take an Accurate Temperature](/thermometer/how-to-take-accurate-temperature) · [Forehead vs Ear vs Oral](/thermometer/forehead-vs-ear-vs-oral) · [Fever Guide](/thermometer/fever-guide) · [Fever in Children](/thermometer/fever-in-children-guide)