Artifact Details Title Vacuum tube type 4KT6 Catalog Number 102731120 Type Physical object Description These are two vacuum tubes, type 4KT6, manufactured by GRadio Corporation of America (RCA), with 9 connector pins. Semi-remote cut-off pentode, 4.5v voltage. Manufacturer Radio Corporation of America (RCA) Place Manufactured Japan Identifying Numbers Model number 4KT6 Stamped on middle of tube in gray. Other number 3K 7424 Stamped on middle of tube in gray. Other number A-23 On middle of tube in gray. Dimensions overall: 2 in x 3/4 in Category Component/vacuum tube