• Marrying the sensor to the digitizer and recorder, this all-in-one seismograph provides exceptional performance for a variety of downhole installations: direct burial, shallow or deepcased holes. The Meridian PH features the latest generation Trillium 120PH class seismometer technology mounted on a leveling system inside a stainless steel pressure vessel. Inherent in all Trillium seismometers, the Meridian PH provides low power consumption, remote mass centering, and a robust no-mass lock design. The Meridian PH is also available for Polar environments.