The new designation convention was applied retrospectively to many of the previously produced types, as well as to those produced afterwards. For example, a Soviet-produced copy of the 6L6 was originally manufactured in the 1940s under its American designation (in Latin lettering), or sometimes a Cyrillic transcription of it, 6Л6. Under the above convention the tube was redesignated 6P3S (Russian: 6П3С). The 6V6 tube became 6P6S (Russian: 6П6С). However, many specialised Russian tubes, such as special military or transmitter tubes, do not follow the above convention.