EF22 is a high frequency pentode, which is suitable for use in all types of amplifiers. EF22 was also a part of many middle sized radio receivers from Tesla factory ( Klasik, Romance, Kongres, Melodic, Harmonie, 619A Dalibor, 620A Máj and others). Tubes are new and tested. Will be delivered in pictured Tesla boxes. Manufacturer: Polam, PL.