This is a business card/card holder for an M5 system notebook, hand-stitched with genuine leather. The main body is made of Tochigi leather in navy, the front of the pocket is made of Tochigi leather in black, and the back is made of navy. It is hand-stitched with navy "Vinymo" thread, and the edges are polished and finished with "Toconole". The width has been extended by about 8mm compared to the M5 refill so that the binding holes are not covered even when cards or business cards are inserted. It should not protrude from the notebook cover, but please check before purchasing. *This item is also listed on other sites. If it sells out on another site first, we may have to cancel your order. Thank you for your understanding.