New Plate Current Matched Quad of Genalex Gold Lion KT88 (6550) Vacuum Tubes These are as close to the original Genalex KT88s as you could possibly get. Made in Russia, they look identical to the originals down to the plate structure. They even have gold plated grids, carbonized screen grids, and tri-alloy plates. It’s hard to get any higher quality in any tube than what the Genalex KT88 has to offer. Tubes are tested and/or matched at full operating voltage with regulated power supply on a Maxi Matcher tester for general mutual transconductance (Gm). In addition, power tubes are tested/matched by plate current (Ip) and preamp tubes are tested/matched by gain. Rectifier tubes will be tested for emissions on a calibrated military grade tube tester. Our goal is to match within 5% with an upper limit of 15% (15% is the industry limit to consider a set). They will be matched by the same parameters (Ip & Gm) but to the manufacturer's standards. Factory testing will be indicated in the item title and description.