This adapter converts the common 1R5 tube to replace the 1L6 tube used in Zenith Transoceanics, and likely other radios as well. The 1R5 works well in the broadcast band but performs poorly, or not at all, on the upper shortwave bands. Thus it is intended for testing, or for applications where the Transoceanic will be operated primarily in the AM broadcast band. Adapter only, IR5 tube not included.