Experience the world of underwater acoustics with our state of the art, cutting-edge hydrophones, designed for precision, durability, and versatility. All HBK Hydrophones deliver a flat frequency response over a wide frequency range. All hydrophones are built with a shielded-element construction; completely waterproof, corrosion-resistant, and are able to withstand high levels of salinity. The instruments provide unrivaled depth, range, and precision when measuring sound in the lab and in ocean research.