The T.A.D. (Tube Amp Doctor) audio tubes we offer are designed in Germany and produced in China to TAD's high standards. The reliability, build quality, and tone of these TAD vacuum tubes are outstanding. TAD 6L6GC-STR, 6L6WGC-STR, 6V6GT, and TAD EL84 power vacuum tube types are clearly some of the best available. All of these are rated for higher plate voltage and power than typical versions of these vacuum tubes. The TAD 6L6GC and 6L6WGC are incredibly popular and long-time best sellers. These 6L6 tubes, along with the other TAD vacuum tubes we offer, have great customer reviews. You can also find our reviews in the Product Reviews section.