This geology/environmental/forestry/surveying field book really stands out as it includes 16 references pages detailing things like conversions, trigonometric formulae and other useful field informations. It has 160 pages (80 sheets) and the dimensions are roughly 12.5 x 18cm. The paper used in this book is cotton based rag paper which means that it is stronger and much more water resistant than traditional wood pulp based paper that is used in regular books. We actively use and recommend this book.
It is a hard cover field book and is great to record your observations whilst in the field. These are very similar to the Rite in the Rain 540F notebooks.