This is our Gold Pin Retube kit for the Dr. Z Z-PLUS Combo Amp. It includes a matched pair of the JJ 6V6S for power, one Gold Pin ECC81 to replace the 12AT7/6201, four Gold Pin ECC83S's, and one GZ34 rectifier. The gold pin preamp tubes provide a smooth and creamy overdrive that lacks the "hair" or grit on the tone that you would ordinarily get from the standard tubes.