The HTD-OBS is a deep-sea hydrophone designed as a secondary sensor for composite perception modules. It features excellent noise floor characteristics and a wide dynamic range. Within the 10Hz-10kHz bandwidth, its sensitivity reaches -170 dB ± 2 dB (Re 1V/μPa). This hydrophone can detect seismic events, marine life, and noise generated by human activities in the ocean, capable of monitoring and recording sounds ranging from marine mammals in the water column to rainfall at the sea surface. Furthermore, the HTD-OBS hydrophone employs a cylindrical structure with its internal sensing components protected by polyurethane material, maintaining high accuracy even in environments with significant temperature and pressure variations. It is widely applicable in the seismic industry for Ocean Bottom Seismometer (OBS) systems and is also suitable for marine cetacean research, making it an ideal hydrophone for marine environments.