VHL series land 3-component geophone string is one of our latest design to provide a practical solution for the requirement of multi-component data acquisition. It has main features as high sensitivity, low distortion, perfect damping, good linear response, wonderful waterproofness and split-hair resolution. Whatever being used in silt, marsh or loose sandlot area, it can also provide favorable performance of earth surface coupling. The general syntonic frequency of geophone is between 8Hz and 40Hz.