The 4 matched Electro-Harmonix 6550 tubes in this lot all have triple micas and gray plates. The black print on the glass has the Electro-Harmonix logo (partial/missing) with 2001 dates codes. These tubes have unknown hours of use. They have been tested at 500V settings on an AT1000 tester. Results range from 61.8 - 63.6 mA for current draw and 6800 (106%) - 7000 (109%) Gm for transconductance.Each tube ships with test results (see photos). Each tube ships packed with the test results shown in the photos. The item "Lot of 4 matched Electro-Harmonix 6550EH tubes, AT1000 tested, 2001" is in sale since Sunday, July 11, 2021. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets". The seller is "chelseawin-mn" and is located in Saint Paul, Minnesota. This item can be shipped worldwide.