Philips and Mullard TY4-500 / TB4-1250 / 5868 high power (450W dissipation, medium gain - mu 28, all 3 types are the same and interchangeable ) triode output tubes. They are new items. As a transmitter tube good up to 30 MHz. The price is PER TUBE. Limited quantities available, please contact us for availability and price. This item is shipped from Britain, in North America or Asia please allow 2 to 3 weeks for delivery.
Here is the spec sheet for this part: http://scottbecker.net/tube/sheets/030/t/TB4-1250.pdf