Own a 24 Hours Ration box, made to the original specifications and copied from an original.
They were designed to fit inside the larger mess tin. They come with the instructions label, as per the originals.
24 Hour Ration Box (single)
24 Hour Rations Guide
For a guide on how to correctly fill the boxes with the correct rations, please take a look at 'The 24 Hour Ration Guide'.