T-64 is really the main battle tank for Ukraine in opposite to Russia where choice was made in favor of T-72. Actually T-64 and T-72 have been producing simultaneously for a long time, however, T-64 was the main tank of Soviet army and used internally while T-72 has been exported to the number of countries.
Despite of the fact that both tanks had many items in common, unlike the T-72, the T-64 has an infra-red searchlight on the left side of the 125mm gun, a different power pack, narrower track, a different suspension, and a slightly different turret. T-64 has been produced since middle 1960s and turned to be the first of a sophisticated new family of Soviet main battle tanks developed as successors to the T-54/55/62 family. It was the first tank to use an autoloader, which reduced the crew to three, gunner and commander in the turret and the driver in the front o f the hull. Also it was the first Soviet tank to use ceramic composite armor.
Nowadays Ukraine operate circa one thousand of T-64, which they have upgraded. Mainly its T-64BV modification. It has improved armor and Kontakt add-on explosive reactive armor. It is fitted with a total of 179 ERA blocks that provide protection against HEAT rounds. Also 10 T-64B that were modernized and ready for export to Congo have been put in service in Ukrainian National Guard. Some of the T-64s of different modification were destroyed during the anti-terrorist operation on the Eastern Ukraine.