In early 1951, Mullard introduced a handy steel container finished in 'Dimenso' - that's posh for silver hammer finish paint. The container was designed to hold 600 cards in six separate compartments. This number of cards would test 750 different valve types. The container featured rubber feet and was sized to be equivalent in length to the depth of a tester so it could sit alongside - provided enough room was left to allow the clamshell top to open! And the price for this marvel of modern engineering in March 1951 was 45s - a snip!