Pocket notebook is conveniently sized and tough enough to survive any of Mother Nature's onslaughts. Notebook repels water， oil， grease and more. Works with Rite in the Rain all-weather pens/pencils， wax markers and crayons in wet or dry applications. Permanent markers and standard ballpoint pens work under dry conditions. Will not work with gel pens， most highlighters， fountain pens or water colors. Paper is wood-based， recyclable， and survives rain， heavy sweat， mud & grime， heat & humidity， oil & grease， sleet & snow， fog & mist. Inside cover includes convenient measurement guides. Universal page pattern allows notebook to be used for journaling or graphing. Mini ruler included on the back of the notebook for quick measurements.