The MH-DW70 is a borehole hammer for inverse VSP and cross-hole seismic surveys. The seismic signals are conveyed to ground by means of clamping wedges. The investigation range is from 20 to 200 meters, depending on the seismic transparency of the rock or soil. The minimum borehole diameter is 70 mm for the MH-DW70. The maximum recommended depth 200 m. The hammer is designed as motor-driven accelerated weight drop. The model is equipped with electric motors and trigger sensor.