Claymo Probe Master of the Great Ustuga - the Mihail Gavrilov Finals - M-O initials - 1755-1775.

The stigma of the test master of Oknishnikov Mikhail Gavrilov with the image of the initials "M" and "O", there is a point between the letters, the year "1755" was also signed.The master was born in 1722, the first test work of the master of the Great Ustyug, (1755-1775) Form: square