Bulk packed with generic ECC803S markings. Great in vintage and vintage style guitar amps. Not recommended for high gain amps.
From the Fenderforum.com
FWIW - I got some JJ ECC803S's from Mike at KCA. Tried one in the head tonight. It has a great balance and opens up the top end a little. Great tube to brighten the amp up a little. This is in a modded head. I assume it would do the same in an unmodded one.