It's hard to say the Thermapen One is truly the world's fastest cooking thermometer — the company says it's as fast as the speed of thought. But I'd say it's impossible to beat.
The Thermapen is built like a pocket knife. A 4.3-inch probe folds out up to 180 degrees, storing in a rubber retainer when not in use. A motion sensor on the front makes it ready to use when picked up. It's powered by a single AAA battery (included), rated to last up to 2,000 hours. A rubber gasket ensures the single-screw battery compartment is shockproof, dustproof and waterproof.
I didn't use a stopwatch, but readings took just one second or less. Temperature readings range from minus 58 to 572 degrees Fahrenheit with an accuracy of plus/minus 0.5 degree F.
As for using it to take the temperature of a human, a Thermapen representative said the company did not recommend it, because of the sharp point on the probe. The sensor is on the tip of the probe, which should be inserted at least ⅛ of an inch into the meat or other food item being tested.
There are some settings to configure. To access them, remove the battery cover. Two small buttons allow you to make adjustments for readings of Fahrenheit or Celsius, the display resolution, screen rotation and the auto-off/sleep mode. (thermoworks.com, $105, available in 10 colors)