Rossi Gear Reducer 10:1 Ratio Type MRCI 80 UO3D from the measurements it appears to fit IEC 100 frame motors the input shaft hole is 28mm the output through hole is 1-1/2" dia. the output shaft opposite the input is 3/4" dia. 

Ratio 10:1
Type MRCI 80 UO3D

New no box this Gear reducer it is a new off the shelf from a closed factory that kept spares for their equipment the Gear reducer may have scratches and dust from being stored without a box. 

[Please Look at all the pictures they are part of the description]

                                                                                   [B1-F1-R2-S5-1]