Every Dono deodorizing carbon training pad consists of 5 layers of materials. The first layer is made of non-woven cloth, which allows dog urine flow through to the absorbent core quickly. The second layer is made of paper tissue, added with dog attractant and baking soda. The third layer is a mix of super-absorbent polymer and fluff pulp, which forms the absorbent core that can absorb and turn dog urine to gel instantly. The absorbent core can hold 4 cups of liquid. The fourth layer is also made of paper tissue. The back layer is made of water-proof PE film, which prevents wetting your floor.