This particular set is the same as the 3-hole military VT-231 version, and tests strong. Special care was taken not to rub off any of the print while testing. The tubes’ test results are displayed in the photos (New 6SN7 Spec 100% = 2,600 Gm). See the photos for physical / cosmetic condition. Notes Regarding Tube Tests. All tubes are tested on an Amplitrex AT-1000 tester in the automatic Fixed Bias Mode (for the most conservative results). Test Results are for a general reference only, and are not a guarantee of performance, nor a guarantee of how they will test on your tester. No real world (audio) performance measurements are taken.