The Telefunken ECC808 Vacuum Tube is a vintage audio component known for its high-quality performance and durability. This particular unit, made in Germany, has a diamond bottom design.  It is untested, only because I don't have a way to test it. Telefunken is a well-respected brand in the vintage audio and video industry, making this vacuum tube a desirable choice for collectors and enthusiasts looking to enhance their audio experience with a piece of history from Germany.