• Nanometrics industry-leading Trillium 120-class borehole seismometer in a slim borehole form-factor is optimized for cased boreholes of 115 to 153 mm, complementing the current Trillium 120 Borehole models designed for boreholes of 152 mm and greater. The instrument is housed in a stainless steel enclosure with a spring actuated hole-lock mechanism, strain relief, and a high pressure marine grade connector.