Russian power triode GS-35B (ГC-35Б) with maximum anode dissipation of 1,5 kW. These tubes are well known in the DIY world and used in many projects. As you can see from the gallery it has a copper heat sink for forced air cooling. Heat sink is removable and if you remove it, you will get the GS-35A version of the tube, for another type of cooling. Longer time stored items, unused and in original polystyrene boxes. Made in the 80's and early 90's.