The paper seems heavy duty, but will not accept ball point pen ink. To write in this notebook I have had to use a marker pen, such as a Sharpie. Ink doesn't bleed through to the other side. Problem is that I have to be sure to carry a marker pen with it which means carrying 2 pens at all times. Maybe that is the nature of this manufacturers' waterproof paper, but I've had other all-weather notebooks that did accept ball point pen ink.
Rating: [5 of 5 Stars!]