I love this thing!
Store your pencil in the hollowed out section of the notebook and you don’t have to worry about popping the binding open when you travel with a pen jammed in-between the pages. 
This really is more convenient than it seems; the people at Suck UK really know how to make some great products.

You can also use the hollowed out section to store a tiny rock hammer, incase you find yourself wrongfully locked away at Shawshank. 

Comes in two sizes; 190x140mm & 125x90mm.  Approx. 7.5 x 5.5 inches & 5 x 3.5 inches.