Cache container
From GeoWiki
Something to hold all the bits and pieces.
A cache container can be any container, however some are more suitable than others. Plastic boxes are popular, as are ex military ammunition boxes. The main thing is to have a container of sufficient size to hold a log book, writing implement and a few swaps. Empty tins such as paint tins have been used. Bear in mind these may rust and the finder may not have a suitable opening tool to hand. If you plan to hide the cache in an area frequented by animals the ammunition box type of container is a good choice as plastic can be chewed through. The container can be left natural or painted to help it blend in with the surroundings.