Seismic Single hyrdrophones

These are individual pressure transducers (9Hz with piezoelectric crystals) with long leads for connecting to Mueller-type take-outs. They are intended to be used in situations where a stream crossing allows the cable to be suspended above the water and the phones can easily be attached and dropped on the bottom to eliminate gaps in the record.  Hydrophone diameter is 1.57" (4cm). Length 8". Each hydrophone has a 20' lead.