Anyone who has ever had a sick child knows what a hassle it can be to take someone’s temperature using the traditional ­method—­slipping a thermometer under her tongue, getting her to sit still for minutes at a time and hoping that whatever reading you get is accurate. That’s why, in recent years, many brands have started to make no-touch thermometers, which use infrared technology to measure core body temperature quickly and precisely. But one model stands out both for its design and its efficacy: Arc’s Insta­Temp (and its more precise, clinical version, InstaTemp MD), which was recently approved by the FDA. Once the device is placed roughly an inch from a patient’s forehead, it spits out a temperature in 2.5 seconds—­coded red, yellow or green, depending on the reading. If you can take a temperature this way, why would you do it any other way?