Hand-operated equipment can be applied for soil research up to a depth of 5 to 10 meter. In this product information leaflet a number of gouge augers are described. Their mutual quality is that they are all fitted with an almost half cylindrical operational part with parallel cutting edges running vertically, justifying the name gouge auger. This operational part may vary in length as well as in diameter. The most suitable length depends on the penetration resistance, the substance of the soil and the required boring depth. The longer the operational part the more vulnerable the auger is to torsion.