2x test

I have a old Seaward RCD tester that tests the tripping time at 1x, 2x, and 5x of the RCD's rated tripping current. It tests 10mA, 30mA, 100mA, 300mA and 500mA rated RCD's, both at 0° and 180°. When was this type of RCD tester in mainstream use, as I have not heard of modern RCD testers being...