Proving Ring is for determining the bearing capacity of sub-grade soils or for compaction control and meets the requirement of ASTM D-420. Consists of a sturdy handle under which is fixed a sensitive proving ring. An extension piece is fixed on to the bottom of the proving ring and carries the detachable penetration cone at its tip. Proving ring capacity is 130 kg and the .002 mm dial indicator is provided, indicates the penetration load applied with a sensitivity of approx. 1/2 kg. division. A calibration chart is provided for the proving ring. Instrument is complete in wooden carrying case.