Heavy-Duty Steel Penetrometer uses the penetration principle to find unconfined compressive strength. Reads 0–4.5 tons/sq. ft. (kg/sq. cm). Results automatically hold when the piston is released. Measures 3/4" dia. x 6-3/8"L and includes a canvas case with a belt loop. For soft soil measurements, order the optional Penetrometer Foot Plate. The plate attaches to the bottom of the Penetrometer to provide additional surface area and ensure an accurate reading in soft soils.