Tung-Sol Tube Upgrade Kit For Fender Excelsior Amps 6V6GT 12AX7 This set includes (2) Matched Tung-Sol 6V6GT power tubes (1) Tung-Sol 12AX7 preamp tube (1) "Gain Balanced" Tung-Sol 12AX7 preamp tube (phase inverter) marked with yellow "Balanced Triodes" Sticker