Relative Density Meter RD-1
It's applied to test minimum void ratio of non-cohesion soil,
whose granular diameter is no bigger than 5mm, thus
to provide data for relative density calculation.
Big metal barrel volume: 250cm3 (dia48x13.9mm)
Small metal barrel volume: 1000cm3 (dia100x127mm)
Hammer weight: 1.25kg
Drop: 15cm
Hammer foundation: diameter 45mm