This fits your .
The Pen Loop. Leuchtturm's self-adhesive pen-holder made from sturdy elastic. Whether a pencil, fountain pen or wax crayon, the Pen Loop is suitable for most sizes of pen. The self-adhesive loop is simply affixed to the inside back cover. So you can carry your favourite pen with your notebook at all times.
Leuchtturm Pen Loop Black - B002CWMAPW