It is used to show the relationship between the moisture content versus dry density and penetration resistance.
It consists of a body housing a spring, plunger calibrated to read 0-40 kg x 1 kg. and a handle. Two stems are provided, a larger stem and a shorter stem, both graduated at 12.5mm. intervals, to indicate the depth of penetration. The larger stem and the smaller stem ate used with needles of larger and smaller areas respectively. Supplied with Needle Point Set comprising on each of 0.25, 0.5,1.5,3.5 and 6cm square and a tommy pin in a nicely polished wooden carrying case.