IMAGENEX MODEL 837 "" Delta T" "is a multi-beam depth sounding system with high resolution and multiple receivers that can run on both personal laptops and professional PCS. Sonar array with 120 ° x 3 ° fan beam, specially for measuring the bottom topography. 3 ° longitudinal beam Angle, can effectively reduce the measurement error. Working frequency of 260 KHz, effective detection distance up to 100m. At close range, the image can be updated 20 times per second, or up to 5 times per second in the 100m range.