At a length of 7.5 m, the borehole probe weighs approx. 750 kg and is divided into three sections for transport. The coupling is hydraulic. The power supply and communication is carried out from above ground via Heptakabel. The SPWD field prototype was tested in the GFZ underground laboratory (Freiberg) and in the KTB (Windischeschenbach) and used in a well at the Piana del Toppo test site of OGS Trieste in Northern Italy.