Made in USA by Sylvania.

Round muddy black plate. Bottom D-Getter.

Nos but no box. Packed in white box.

Made in USA by Sylvania.
Metal base, half silver tube. Great of 6SL7 ever made in USA. One of the most treasured of the 6SL7 types and are characterized by excellent low level detail resolution, very immediate sounding with a lot of lower level slam. This version is very very rare.
Nos but no box. Packed in white box. Matched pair are available

Made in USA by RCA (1960s).
Muddy black plate, Triple mica and Double D-Getter with five supports.
Most of muddy black plate version are made by RCA.
Very warm sweet sound, great on voices and jazz. Long life tube (10.000 hours)
Ligh used but test excellent. Packed in white box. Matched pair are available.

Made by Tung-Sol (1943).
Like the Sylvania Metal base. This is one of the best tube ever made in USA with half smoke glass, Round muddy black plate. Round mica on the top (better than oval mica version).
Nos in original box.  Matched pair are available.

Made in W.Germany (1957).

Round white steel plate with bottom D-Getter. Very good tube, balance sounding.

Nos in original box. Matched pair are available.