Electron tube 6CC31 Tesla is double triode, designed for HF and LF amplifiers, for HF oscillators and mixers for frequencies up to 600 MHz. 6CC31 Tesla is direct replacement for american 6J6 and european ECC91 tubes. It is also direct replacement for russian 6N15P (6H15П). Tubes are tested on BM215A. Produced in the 50's and early 60's.