From their website:
Let your creative minds go wild, this exciting competition is open to everyone.
As you may know the Mantic Messenger Bag comes with 2, 48mm blank carry cases, we will soon also be selling the blank carry cases alone. We thought it would be great for our fans to have their say as to what we should print as a cover sleeve, so we will print the winning design and wrap it around these products.
We would love to see your designs, no matter how wacky or insane. All designs that pass the Mantic committee (don’t worry anything goes……almost) will be displayed in the ‘Design a Sleeve’ gallery – allowing others to use your designs to personalise their own cases.