I bought the sample patch for my 11 lb dog to use on the balcony. It works perfectly with a puppy pad underneath that I just switch out every 2-3 uses. The holes in the grass allow for easy draining/washing, and the rain naturally rinses it. It's been over a week with no smell. She didn't use it at all the first day, but on the second day, I waited until she needed to use the bathroom really badly, and put her on the balcony. She had no choice but to use it and I gave her a treat afterward. Now she knows to scratch at the balcony door every time she needs to go. I would most likely purchase this again.