A vintage Russian vacuum tube, 6C33C (6S33S) made by the Ulyanov factory around 1972. These are used as series pass elements in voltage regulators, and work well as audio power triodes. For the old tyme radio folks, this has the same "septar" base as the American 832A and 829B. This particular tube is a dud, as evidenced by the milky white top, (which is normally a shiny silver color), which indicates that a leak let all of the little vacuum particals out (or more realistically, it was having a Bad Air Day).