This Tung-Sol 12AU7W / 6189 tube is amazing. Patterned after one of the most durable military grade tubes ever built, the new Tung-Sol 12AU7W / 6189 tube has been further upgraded to provide superior audio performance in addition to nuclear survivability. With industrial construction, this Tung-Sol 12AU7W / 6189 provides inspiring transient impact with a weighty, dynamically full response. Perfect for phase inverter and reverb driver positions. Equally capable in both musical instrument and audiophile applications, the full musicality of this tube is amazing ... making this Tung-Sol 12AU7W / 6189 tube a truely worthy tube.