Rite in the rain is a well known established brand as-well as renown for creating fine products. 

Bound together with a field flex cover and tough combined spine completing it being totally waterproof. 

They also include conversion charts in CM'S and Inches. 

Dimensions for this Notepad are 3.5 x 6 Inches 60 pages, making it 120 in total Gridded sheets.  

In wet weather use crayon, all weather pen, pencil. When its dry - a normal ball point pen or pencil is fine.