Poland under Russia, Nicholas I, 3/4 rouble=5 zloty 1840 MW

A nice piece with well-preserved details.

Obverse: crowned eagle of the Russian Empire, on the sides of its tail the initials M-W, in the outer rim the legend:
ЧИСТАГО СЕРЕБРА 3 ЗОЛОТНИКА 15 3/4 ДОЛЕЙ;

Reverse: in laurel and oak wreath inscription:
3/4/РУБЛЯ./5/ZLOT-/1840;