Hearing protection devices is a concept within audiology, occupational health, and acoustics that defines technologies engineered to reduce the level of sound energy reaching the ear, thereby preventing noise-induced auditory damage. As a research field, it systematically investigates the performance characteristics, user acceptance, and real-world effectiveness of various preventative interventions against hazardous noise exposure. This research area is characterised by studies on acoustic attenuation properties, comfort, fit, and the factors influencing consistent and correct usage, with significant implications for public health and occupational safety through the mitigation of hearing impairment.