Dog Grass Pad with Tray,40″X27.5″Large Artificial Turf Grass Potty,XL Reusable 3-Layer Dogs Pee Potty Grass Pads, Easy to Clean Portable Dog Litter Box for Indoor/Outdoor Potty Training Toilet. 3-Layer Design: The dog grass pad is a 3-layer system, artificial grass + drainage grate + big tray, not need to assemble, simply place the turf on top of the grate and place them in the durable base.