Dog Rocks are all natural, safe Australian grass saver and lawn treatment solution that helps prevent your yard from burn marks caused by dog's urine. It acts as a neutralizer and filter out impurities in water, such as tin, ammonia, and nitrates The impurities are generally passed out through urine. When they come in contact with grass, it results in grass burn, typically a dead yellow patch of grass. Dog Rocks make the water source cleaner for your pet and remove grass marks. Water without impurities from Dog Rocks will actually help your pet to fertilize your lawn. Your grass will start looking greener and fresher in no time at all. Dog Rocks have absolutely no harmful side effects to dogs, and even if your dog shares his bowl with the cat or other pets within your household, it is fine for them to drink this water too. There is no change to the pH balance to either of your pet's urine, so it is naturally safe Dog Rocks are a naturally mined product so the rock sizes may differ from every pack, but the weight of each pack is always consistent. There are usually 1-3 rocks per pack. One pack of Dog Rocks will last you for two months and need to be replaced after. Please note that the rocks from one pack or 200g need to be added to a half gallon of water in your dog's bowl It is important to make sure that your pet drinks solely from this source of water, as any other water that they drink will not have been filtered by Dog Rocks, and will therefore reduce the benefit of Dog Rocks. Top off the existing water in the bowl everyday rather than replace the water. Change the water when the dog is least likely to consume large amounts of water With Dog Rocks, you and your dog will enjoy beautiful, greener than ever grass without worrying about yellow, brown and burn marks all over your lawn again.