Made entirely out of Tyvek Waterproof, tear-proof, and a patented binding system that can be bent without damaging the binding or sheets All weather notebook. Ideal for working outdoors. Handmade and curbside recyclable Lined and ruled pattern 140 pages 3.5" x 5.5" For best results, use a ballpoint pen. Not for use with pencils or water-based inks. The Tuk Book is the world’s most durable notebook. It is made entirely out of Tyvek. It was designed to be your companion, no matter what your day entails. It is waterproof, tear-resistant, and incorporates a patented binding system that allows it to be bent without damaging the binding or sheets. Wear it in your back pocket or throw it in your bag – either way, don’t worry about it! Like a fine wine or a good pair of jeans, your Tuk Book will get worked in and better with age. For best results, use a ballpoint pen. Not for use with pencils.