This sale is for 3X Very Good 6SN7GTB Tube RCA Branded Westinghouse with code  letter code MU and MR ,    black facing plate tested very high with a result  of 2650/2600 , 2450/2400 and 2500/2700 GMT on my Stark Tube tester 9-66  where the minimum working is 1260 GMT and the maximum rated for new is 2000 GMT each triode.

               

                                          Shipping is $18 for Canada , $15 for USA and $25 for others countries.