For Sale is a Nice Pair of Premium Sylvania 12AX7 Tubes with Covers, 17mm Plates, Balanced, Matched Plates, Same Codes Testing done via new Amplitrex tester: Tubes tested: 100/106 & 106/106% GM These sound very nice in our Citation Pre-amp. We combine shipping, when buying multiple items please wait for your final invoice. See our other items for more great listings. Safe shipping via USPS,