KT808A: NPN silicon power transistor, 120 V; 10 A; 50 W;
Produced  in the former Soviet Union; the retail price is printed on the transistor: 7 rubles, 50 kopeks
<a href="//commons.wikimedia.org/wiki/User:Mister_rf" title="User:Mister rf">Mister rf</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>