I ordered this tray as we will be using it on our boat which has an aluminum deck and will not slide around on the deck when the boat rocks or heels. My husband thinks I should have gotten the size of grass that would fit the silicone tray. Our dog is almost 50# though so I would like to try this 24x24 size. We haven't had a chance to take it to the boat yet and will just have to wait and see but we can always cut down the size of the grass patch to fit the tray. My idea had been to cut one long edge of the tray off so the extra grass would lay directly on the deck. Either way will work.