Can someone tell me about this tube? 6C19N-B

I am helping a friend sell off a large collection of tubes and I have a case of 6C19N-B tubes. Not sure how to market them for sale.

Very few people will want these. They are a very low power triode that is not a direct substitute for a more common tube like EL84/6BQ5.

They have been used in some hi-fi gear, the Transcendent Sound amp and, if memory serves, the Little Dot headphone amp. There may be a few others. But they are common, cheap, and do not have very many audio applications.
Thank you for the reply,this is helpful.

For what it's worth, most tube vendors price the tube at $20.00-30.00 per tube, but my assumption is that is because volume of sales are so low that it isn't worth it for them to sell any less expensively. If you ordered from the Eastern block, in quantity, you would pay much, much less than that.