BioLogues Cahier Collection. Organize your notes with a BioLogues cahier cover in colorful leather, kraft-tex leather alternative, or canvas. Covers in this collection are designed to fit either pocket-sized 3.5 x 5.5 inch or large 5 x 8.25 inch cahier notebooklets, including Moleskine and Field Notes brands. Each cover comes pre-loaded with an empty Moleskine cahier ready to be filled by you. Personalized cahiers and cahiers engraved with original designs are also available.