1904 model Testing set 1900 model Testing set Hand Generators Meggers and other insulation testers Evershed and Vignoles Timeline Evershed-Vernon Potentiometer Earthometer Tester Series 4 Bonding Tester battery megger tester cat 4003series 2 bridge megger battery megger tester tester cat 4022 Evershed's Moving Coil Ammeter Voltmeter