Attention, the tubes are not in the original polystyrene packaging, for this reason some tubes may have scratches or very slight bumps... Military equipment, "OTK", high reliability. Military quality check passed (rhombus) The tubes are never used. Old stock. THE BIND IS FOR 2 TUBES GI-7BT, MILITARY,TROPIC!!! High quality made for the military equipmentMade in USSRMilitary equipment Type Pulse tetrodeCathode type Oxide, indirect heatingApplication field Oscillation UHF in continous mode and pulse mode with anode modulation in special equipmentBrief application OscillationDimension 110,5mm X 65mmMass 330 gNormale anode voltage 1,3 kVFilament voltage 12,6 VFilament current 1,8 - 2,05 AMutual conductance 20 to 26 ma/VOutput power 350W/ 11 KW in pulseMax. anod voltage 2,5KV/9 kV in pulseMax. operating frequency 18 cmAmbient temparature ,°C -60 to +100Relative humidity at up to +40 °C 98% Decoding the triode marking: GI-7B GI - letters defining the type of lamp: GI - generator pulse; 7 - the number of the ordinal number of the development of this type of lamp; B - a letter indicating the type of forced cooling: B - air. T- design