All-weather paper Polydura cover Rulers, conversion charts, and map scales printed on the cover Field-Flex covers easily conform to pockets or packs, yet spring back into shape. Made with archival grade, weather-resistant 20# paper. Refer back to your notes even on the roughest job site with a notebook that survives rain, sweat, grease or anything else the job site digs up. Impact-resistant Wire-O doesnt get bent out of shape when tossed around in packs or your pocket. The Polydura cover 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.