I really love Arches paper and particularly their watercolor blocks. They are truly sealed on all sides (except for small are where you insert your palette knife to separate the pages). I've used other blocks that separate right away and it's annoying; I buy blocks for a reason and if they separate before you even use them, may as well buy loose papers. The paper has consistent, even "tooth" and hold the watercolor beautifully while also providing you time to work the paint as needed for blending/blotting, etc.