2.5Hz-3Hz vertical,horizontal and tri-conponents geophone. CDJ low-frequency geophones, 1Hz, 2Hz, 2.5Hz or 3Hz, are widely used in deep seismic prospecting, earthquake monitoring, microseismometry in engineering, surface wave survey and low frequency measurement in other fields.SPECIFICATIONS CDJ-Z2.5CCDJ-P2.5CCDJ-S2.5CCDJ-Z3CCDJ-P3CCDJ-S3C VerticalHorizontal3-CVerticalHorizontal3-CNature ...