Amphenol Wilcoxon H23-080 Microphones Test & Measurement hydrophone, small, versatile, self-amplified, and shielded, -174 dB re 1 V/uPa, 5 Hz to 100 kHz a. +/-3 dB, 0.14 dia., twisted shielded pair integral cable, 10 ft standard length, rated to 1000 PSI / 680m operating depth.