TUBE INFO: These tubes are Brand New in factory retail boxes from the New Sensor Corporation. They"re another fine example of the reproduction tubes NSC is producing under the Tungsol trademark. What are they like? With out question, these tubes are some of the most stable, low microphonic and linear constructed tubes currently being produced. Top that off with loads of gain and very musical sounding tube and you will find these very hard to beat. Especially for the price. Each of these tubes was checked out on a Vacuum Tube Characterizer from VTV which along with gain and shorts, also tests for NOISE and MICROPHONICS. We also go one step further by double-checking them on a Maxi-Preamp Tester to confirm the VTV"s measurements. Check out VTV and Maxi"s websites for the spec"s these great testers. We stand behind these tubes 100% for **Authenticity** and being NEW. If you are looking for the genuine re-issue Tungsol 12AU7 made in the Reflektor plant in Saratov, Russia and sold by New Sensor Corp. then look no further then right here.