12Ž1L (12Ж1Л) is a HF pentode for frequencies up to 200 MHz. It is also known as 12ZH1L. For better manipulation it is equipped with small bakelite handles. It is very similar to the russian 4J1L, but is has different heater. 12J1L is also very close to the old military tube RV12P2000, but is is not a direct replacement. RV12P2000 has totally different base. New old stock tubes. Made in the 80's and early 90's. Manufacturer: Svetlana, St. Petersburg.