6SN7GTBBranded GeRound TipBaseBlackBottle HeightHalfBottle ShapeSkinny BottleCountryCanadaGlass ColorClear GlassMicaDoublePermanentidrcer8cluPin ColorSilver PinsPlate ColorBlackTip ShapeRound TipMore 6SN7GTB type tubes6SN7GTBBranded Relco6SN7GTBBranded Hit-RayItt6SN7GTBBranded Sylvania6SN7GTBBranded RCA6SN7GTBBranded Amperex6SN7GTBBranded Sylvania6SN7GTBBranded CEI6SN7GTBBranded G.E.B.6SN7GTBBranded PhilipsRogers6SN7GTBBranded RCAMore tubes branded Ge6SN7GT, VT-231Branded Ge5670WBranded Ge5751Branded Ge12AX7Branded Ge7591ASylvaniaBranded GeGL-5670Branded Ge6FQ7, 6CG7Branded Ge12AX7WABranded Ge12AX7Branded Ge12AX7A, ECC83MullardBranded Ge