Fully prepared for any challenge mother nature throws at it, these notebooks can handle any weather encountered in the field. Impact-resistant Wire-O doesn't get bent out of shape when tossed around in packs or your pocket. The Polydura cover material creates a tough but flexible outer shell defending your notes from scratches and stains. Rulers, conversion charts, and map scales printed on the cover prove handy in the field. Wire-O binding Polydura cover Rulers & reference