Method to choose the ideal size of earplug

The last version of 3MTM Combat ArmsTM earplugs was designed to meet the hearing protection needs of the French armed forces. This earplug uses triple-flange-design fits in three sizes (small, medium, and large) allowing the best adaptation to all morphologies. The individual choice of the size of the earplug is the major problem to have an adequate protection: how to choose the ideal size? Three methods were assessed in the current study. The first method was based on the observation of tympanometry tips fit. The second was a commercial device allowing to check the attenuation of the earplug in situ. The last one was based on the detection of leak in low frequency with an instrumented earplug. The objective of this study was to compare these three different methods. An assessment test with 106 soldiers was performed. Each soldier was tested with the three methods, in a different order. The results of the different methods are presented and compared.