That would be the T-34 76F with commanders cupola.

"As T-34 76D but with cast instead of welded turret. Mechanical improvements including five-speed gearbox. Production terminated after 100 vehicles in favor of T-34/85. Details as T-34 76D."

from tanks of the world, Chamberlain & Ellis.

Unknown how many units had the cupola. (the Germans did attach cupolas to some captured models, and that one is "German" looking, (instead of the "roundier" looking top edge in the picture I have.)(then again perhaps not, since the vision ports are the same)

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Morbius, Morbius! Something is approaching from the Southwest. It is now quite close.