Our usual tube tester is the AVO VCM163. One of the best testers in the world. We have been in the tube business since 1981. We have 1,000,000 valves in stock.LARGER QUANTITIES, IF AVAILABLE, CAN BE LISTED ON REQUEST. Our opening hours are Mon - Fri 8am - 4:30pm. The item "300B Billington Gold Special Edition matched pair 2 pieces NOS tube valve" is in sale since Thursday, October 3, 2019. This item is in the category "Sound & Vision\Vintage Sound & Vision\Vintage Parts & Accessories\Valves & Vacuum Tubes". The seller is "billington784961" and is located in Billingshurst. This item can be shipped to North, South, or Latin America, all countries in Europe, all countries in continental Asia, Australia.