152 mm towed gun-howitzer M1955 (D-20)
The 152 mm gun-howitzer M1955, also known as the D-20, (Russian: 152-мм пушка-гаубица Д-20 обр. 1955 г.) is a manually loaded, towed 152 mm artillery piece, manufactured in the Soviet Union during the 1950s. It was first observed by the west in 1955, at which time it was designated the M1955. Its GRAU index is 52-P-546.
Additional Information: en.wikipedia.org/wiki/152_mm_towed_gun-howitzer_M1955_%28D-20%29