Want all the gain you can get from your Ultra 60? This is our High Gain Option Retube Kit and it contains four handpicked High Gain ECC83S with one being current balanced for the phase inverter in V4. The default power tubes are a matched pair of the JJ 6L6GC’s but you can configure this kit to use the JJ 5881’s by clicking on the "Customize" button! If your amp is a combo amp then please let us know in the comments section and we will ship your kit with the special Double Mica 6L6GC’s which will greatly reduce any tube rattle.