This is a gridded Traveler's Co. notebook refill with lines in 5mm intervals on white pages. This refill is for the passport sized Traveler's Notebook.
This gridded refill is excellent for drafting graphs/boxes or even as a guide for writing and illustrating! Japanese MD Paper is used in these refills which means the paper is fountain pen friendly and bleed resistant.
Here are some more passport sized refills for your Traveler's Notebook.