It is a simple concept, a pen that has a compartment to store and transport dice.  With this in your pocket you will always have everything you need to play thousands of dice games, all you need is the cocktail napkin (or equivalent).

The Dice Pen comes in many varieties of dice from Standard Dice, to CCG Dice, 5mm Mini Dice, Backgammon Dice & Fate Fudge Dice.