Ground penetration radar is cool device which allows you to see what is below earth surface. The principle is same as the radars which operates at air. They send pulses and sense the reflections of this pulses back. When the surface is not consistent you get reflections which allow you to “see” cavities of metals under the surface, some GPRs can scan as deep as hundred meters below the surface. This is ultimate tool for all treasure hunters, but also very useful if you want to see water and other fluids underground.
We spotted interesting post at our forum for GPR made by company from Plovdiv with LIME2.
The device looks very nice in the custom box they made:
The GPR has antenna and WIFi connection so you can connect and visualize the results with any device: