Quality vintage soviet ceramic tube sockets PLK7-D55 (ПЛК7-Д55) for miniature 7-pin tubes. Sockets are equipped with removable steel retainer. It is suitable for tubes like 6L31, 11TA31 from Tesla, etc. After very easy removal of the retainer they may be used for all heptal tube types. New old stock, directly from the factory packing.