Thank you for viewing. This is a set of three vacuum tubes: 12AU7 (Toshiba) and compatible 6189 (Philips JAN6189W and possibly Sylvania 6189, but the printing is unclear, so I apologize). I purchased these, along with others, from a used audio equipment store a couple of weeks ago, and have confirmed their operation in a self-made kit headphone amplifier. Each has been used for only a few hours. As you can see in the photos, they are old, but I think they can be used for testing, such as finding your favorite vacuum tube. I will pack them carefully and ship them in simple packaging.