Our XL DoggieLawn FLEX-TRAY is a functional and economical solution for the XL DoggieLawn grass pads (24 x 48 inches). It's made with flexible, waterproof, PVC fabric and intended to be placed directly underneath our indoor dog potties (for large dogs over 45 lbs or small dogs who simply like larger spaces). As opposed to the regular XL puppy potty tray, the FLEX-TRAY is not rigid and does not have side walls. Grass not included with the training tray for dogs.