File:Vintage EICO Tube Tester, Model 625, Metal Cabinet, EICO Electronic Instrument Company, One Vacuum Tube (6H6), Made In USA, Circa 1950 - 1952 (36078986142).jpg - Wikimedia Commons
File:Vintage EICO Tube Tester, Model 625, Metal Cabinet, EICO Electronic Instrument Company, One Vacuum Tube (6H6), Made In USA, Circa 1950 - 1952 (32892390481).jpg - Wikimedia Commons