This is a matching pair of 2 vintage Ken Rad mil-spec 6SL7GT tubes.  Black plate, foil getter, round mica.

Ex- military surplus, opened, tested and repacked (by the military) in 1971 but not used.  These were selected from a lot of 20 new tubes from the same batch and FULLY MATCHED both side to side and as a set of four using a modern CURVE TRACER.   (I also test with a common AVO 163, but the computerized tracer is much more accurate, of course) 

These have the plastic military sleeving (for durability and to reduce microphonics) but this can be removed, if you want to, using a stanley knife.  (See the last pic but note that all tubes in this set of two still have the sleeving fitted.)

FREE post to anywhere in the world.

See my other listings for more vintage and modern tubes as I clear my 30 years collection of vintage audio.