Do you like fat mids a more vintage tone and little extra high end sparkle? This is our ECC803S V1 Option Retube Kit for the Carr Mercury. It uses a Long Plate ECC803S for V1, an ECC81 for V2 and an ECC83S for V3. The default power tube is a single JJ E34L. However you can configure this kit to use a JJ EL34II, EL34, KT77, 6CA7, 6L6GC, 5881, KT66, 6550 or KT88 by clicking on the "Customize" button!