IEC 60500:2017 specifies the relevant characteristics and properties of hydrophones in the frequency range 1 Hz to 500 kHz, and specifies how to report these characteristics. Provides guidance on the choice of a hydrophone with appropriate performance for a specific application. This standard is applicable to: - hydrophones employing piezoelectric sensor elements, designed to respond to sound pressure in water and measure underwater acoustical signals; - hydrophones with or without an integral pre-amplifier. This new edition includes the following significant technical changes with respect to the previous edition: - the format and scope of IEC 60500 have been changed to be compatible with other IEC standards; - the upper limit of the frequency range of hydrophones has been expanded.