These nursing stickers are made of 100% vinyl that is waterproof, heavy duty, ultra thick and UV resistant. Those other stickers you find on Amazon will not stick to A LOT of surfaces because they use an inferior adhesive. We have stickers that stick to painted cinder block. Those other guys fall off the refrigerators a few weeks after application. They are easy to tear. You will not find a thicker, more durable sticker on the market.