Packing List: You will receive 30 pieces of potty stickers in the package, 15 patterns in total. Each piece is about 7cm/2.75in in diameter, perfect for 's potty training. Easy to Use: First, peel off the backing and stick the sticker on a clean, dry potty; it will stay black. When the child uses the potty, the heat from the action will reveal a cute pattern. After rinsing the potty with cold water, the sticker will turn black again, ready for the next use. Premium Material: These stickers are made of great quality thermochromic paper, adhesive and PVC material. They are sturdy and thick, with strong adhesive properties, turning black below room temperature and revealing colors when heated, not easy to break and damage.