"Our front cover picture shows a batch of High Speed Valve Testers undergoing their final tests at the Mullard Wandsworth factory. Not only is each individual component checked, and where necessary measured, before assembly, but in the final test a series of measurements are taken on every instrument using a Valve Volt Meter. These tests are so arranged that the accuracy of all components and the effectiveness of all the switch contacts are fully checked. From time to time individual testers are, in addition, subjected to life tests simulating over two years' normal operation."