Shuguang Treasures, CV-181-Z (6SN7). These are the tubes you hear so much about. They have approximately 300 hours of playing time on them. For additional information, its best to check out the reviews online. There are tons of reviews and pictures available there. I purchased these new from Grant Fidelity less than a year ago as Grade A Premium, matched, per their standards. I am giving them a conservative 7/10. All tubes are in their original packages, with original test certificate. Paypal, add 3% , personal check upon clearance, Buyer pays USPS shipping.