ZOENHOU 6 Pack A4 Grid Notebook, Kraft Cover Graph Paper A4 Pad 5mm Square Grid Pages, 200 Pages/100 Sheets Spiral Bound Grids Notebook, Squared Wirebound Journal Bulk, 8.2 x 11.4 Inch

The cover is stiff enough although I would prefer it slightly thicker. The number of pages is adequate. The squared ruled lines are just the right density and are not overpowering. You can use the squares to help align diagrams and text without feeling you are writing on a wire mesh.But best of all, you can use a proper pen without the ink bleeding through. The paper itself is slightly off-white but this adds some character.