Want the smoothest richest tone possible from your Rocket 44? This kit contains a matched quad of JJ EL84's for the power section. Three Gold Pin ECC83S's for V1 thru V3 and a balanced Gold Pin ECC83S for the phase inverter in V4. Just let us know in the comments section if you're looking for an early breakup, a moderate breakup or a later breakup for more headroom in which case we will choose the coolest grades we have available for the power tubes.