Chinese tube 6N1 is a direct replacement of the russian tubes from the 6N1P (6H1П ) family. It is used in many amplifiers, which are recently manufactured in China (Fatman, Yaqin VK-2100 and similar). Alternatively it may be used instead of the E88CC or 6922 tubes, but you have to be careful, because there are some important differences. The Beijing 6N1's are drawing considerably more heater current: about 600 mA, comparing to the ECC88/6922/6DJ8 tubes, where it is about 365 mA. In some cases, direct replacement without any discussion with the manufacturer, may end up with damaging of your equipment. Please discuss this with the manufacturer of the equipment. New old stock tubes in original boxes - NIB, manufactured in the 60's.