These are the SED Winged "C" 6L6GC tubes - amazing. These tubes have about 150 hours on them, and sound sublime. They were all purchased from TheTubeStore.com as new, and are all matched perfectly and marked "20". Please see reviews on thetubestore.com for more information.
I have 8 of these tubes - so will list all 8 in the same listing. If someone needs only a portion of those - I will sell and relist (price is $100 a tube).
I used these in my MC240 amplifiers.