Also known as a magnetic fusion drive, or a mega-ion drive.
A staple of high end sci-fi is the replicator or the nano-assembler. There is a much more practical and less technomagical way to achieve the same goal. The exciting thing is that this technology exists now, and we're getting much better at it.
A small, enchanted chest, 2 feet on a side. It is of some dark wood with fantastical images graved upon it. Worn leather straps act as hinges and a simple toggle keeps it closed. Anything placed within it, with the lid closed, becomes accessible to anyone with one of the other 5 identical chests. Once it is taken out of any one of the 6, the chest is empty again. Perfect for passing messages or small items between widespread groups, such as ships at sea and their ports of call or generals on the field of battle.