Hi there Edelgado, Thanks for choosing Next Day Flyers in your printing requires. We have now a wide variety of cardstocks for flyers. Apparently, we do not need a water-proof material although Now we have drinking water-resistant cardstock. These are typically the most popular flyer and postcard sizes for flyer https://mysocialquiz.com/story4366735/5-simple-techniques-for-flyer-printing