Pair Sylvania JHS 12AT7WA Tubes - gray plates, triple mica, square getter, test NOSAll have gray plates and large halo getters. All have been tested on my professionally-calibrated Hickok 539B tube tester. Minimum transconductance for a good 12AT7 tube on this tester is 2500 umhos. Transconductance values for the pair are: 4700/4600; 4400/3250. I can mail these within the U.S. by USPS First Class Mail for $4.00 or by Priority Mail for $6.95. Pay Pal adds 3% for domestic sale and 4.5% for sale outside the U.S.
| 
