The cover is designed for a 5 x 3.5 Inches (12.5 x 9 cm) passport or a small notebook. 
This is a unique piece, I created this one only.
Handcrafted in Canada from 100% premium Veg-Tanned harness leather. Finished with generous amounts of oils & waxes, harness leather is durable and weather-resistant. Over time, your cover will age and the patina take on its own unique character.
Leather Type: Oak-Leaf Veg-Tan Sides: This premium imported veg-tanned leather is tanned using a tannage that produces leather with excellent tooling and embossing properties.  
✔ VERSATILE Ideal for your passport, travel notes, or wherever your journey takes you.
✔ ATTENTION TO DETAIL This notebook is carefully crafted for quality. You'll love the look, feel, and the fact that it won't fall apart like some notebooks
✔ PERFECT GIFT - A must-have for all travelers and an ideal gift for your family and friends, or even yourself, this distinctive refillable journal will help words flow freely. Ideal for any writer artist or anyone simply wanting to do some high-quality note-taking, This leather notebook is a great and classy way to record your life
✤ Bi-Fold Thick Heavy Duty Passport and Notepad Cover - Holder
✤ Tribal carving on both sides
✤ Premium full-grain Veg Tanned harness leather
✤ Hand-stitched with military parachute-grade thread
✤ Hand-burnished leather Edge
✤ Great design for travel or for everyday use
✤ Very strong construction, this will stay with you for a lifetime
✤ Looks nice and so easy to carry by Men & Women (Unisex)
✤ This is a great gift and it can put a smile on faces
✤ You will love it because it's compact and not bulky
For refill 
Traveler's Pocket Notebook Refill Inserts - Lined Paper - Set of 3 | Passport Journal Size | For Small Refillable Travel Journals, Diaries and Notebooks - 5 x 3.5 Inches (12.5 x 9 cm) B7
https://www.amazon.ca/gp/product/B0783511P2/ref=ppx_yo_dt_b_asin_title_o07_s02?ie=UTF8&psc=1