Soviet ultrahigh frequency triode 6S17K-V (6C17К-В) is a tube enclosed in metal-ceramic case. Outer Metal parts are silver plated (the darkened ones). This small tube was already used in some of the DIY amp projects with very good results. Its weight is only around 5 g and service life is not less than 2000 operating hours. New old stock tubes in original boxes (please look a the gallery).