We recommend both, of course! The Wet Erase Pen is best for things that don't need to be updated often, like your Ability Scores. The Dry Erase Pen is better for things that change often, like hit points or spell slots. Regardless of which pen you choose, you'll find a smooth writing surface on your HeroBook that wipes clean after every use. The dry erase pen includes a felt eraser nib to easily erase, but is more prone to accidental smudging. The wet erase pen requires a small amount of moisture to erase, but is highly smudge-resistant.