Maker's Name: 
80 × 11 × 12.5 cm

A probe in the end of a tube is lowered by a thin steel hawser down a borehole. Probes may be designed to measure such parameters as pressure, temperature, electrical resistance or magnetic fields. If several holes are bored, measurements in the holes can give a stratigraphic picture of the earth in the vicinity. Data is returned via the tube casing and a thinner tube down the centre, forming a coaxial cable. There are coarse and fine threads connecting tubes. Probes appear to have fine internal threads, and extension tubes coarse inner and outer threads.