I have a pair of Tung Sol 6550 pulls that test new at 78 and 80 on a Hickock 118b push card tester. $100 delivered USPS insured. One of the tubes has lost most of the guide post which in no way interferes with the tube operation or performance. These tubes came out of an old unused for years Lesly amp I got at a small church. So I guess they were driven by a little old lady on Sundays. Also this is a small church so she didn'ty drive them hard as the testing attests to.