Want all the gain you can get? This is our High Gain Option Retube Kit for the Mesa Mark Five 25 Amps. It contains one standard ECC83S for the verb in V5 along with five handpicked High Gain ECC83S's with one being current balanced for the phase inverter in V6. The default power tubes are a matched pair of the JJ EL84's but you can configure this kit to use the JJ EL844's for an earlier breakup by clicking on the "Customize" button!