This is a matching set of 4 vintage Ken Rad mil-spec 6SL7GT tubes.  New, never used.  Circa 1940s production. Tested for emission and shorts with an AVO 163 tester and  FULLY MATCHED both side to side and as a set of four using a modern CURVE TRACER.  

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.