We present you a new model – crack monitor zi-3d. This device is designed for triaxial monitoring of cracks with high accuracy. On the two axes, you can track the changes visually, using the scale of the monitor. And for a three-axis monitoring, a caliper should be used with a depth gauge. Our development has been used in Russia for more than 5 years and has proven itself well. The figure shows the principle of operation of the crack monitor and its design.