Pup-Drain™ is a polymeric sheet designed to allow for optimal drainage of Pup-Grass™ Its impermeable core works well on slabs/Indoor surfaces as it protects urine from being absorbed by porous surfaces like concrete, slate, or tile. Pup-Drain™ creates a void for airflow and keeps synthetic grass away from liquid waste. The dimpled design also creates a channel for liquids to travel to drains or soil.