Tung-Sol Tube Upgrade Kit For Fender Super Sonic 100 Heads 6L6GCSTR/12AX7/12AT7 This set includes (4) Matched Tung-Sol 6L6GCSTR power tubes (7) Tung-Sol 12AX7 preamp tubes (1) Tung-Sol 12AT7W preamp tube (1) "Gain Balanced" Tung-Sol 12AT7W preamp tube (phase inverter) marked with yellow "Balanced Triodes" Sticker