The ISO 11904 describes two procedures for the direct measurement of sound under communication headsets. For the Microphone in a Real Ear (MIRE) technique, a specially trained individual must insert a miniature or probe microphone in the worker's ear canal. Although this technique provides the most direct estimate of sound exposure to the worker, its invasive nature could restrict his/her movement, and the positioning of the microphone or probe can be problematic. The ISO 11904-2  specifies sound measurements on an acoustic manikin. The standardized manikin simulates the changes that happen to sound waves as they pass a human head and torso. An indirect calculation method has also been proposed that can serve as a basic tool to predict noise exposure in workplace settings where communication headsets are worn.