Dog Rocks Prevent Grass Burn Marks, 2 Month Supply WHAT ARE DOG ROCKS - Dog Rocks are made from naturally occurring paramagnetic igneous rock mined in Australia, and provide a 100% natural solution to urine burn patches on lawn, shrubs and box hedge caused by your dog. Dog Rocks do not affect the pH balance of your dog's urine and is safe for all household pets. HOW THEY WORK - Dog Rocks work like a sponge, absorbing excess nitrates and other trace elements from your dogs water that cause urine to burn grass. By simply placing 200 grams of Dog Rocks into a half-gallon of water in your pets water bowl, your lawns will start to look greener and fresher. SAFE FOR YOUR PETS - Dog Rocks have been laboratory tested and are safe for your pets. Your doggos and puppers be happy, just like you when you see those burn spots start disappearing as Dog Rocks takes effect. NO MORE BURN SPOTS - Within 3-5 weeks, you should start to notice a change in your lawns appearance and new urine patches should not appear. If they do, verify that your pets water bowl is their primary source of water and that it does not hold more than a half-gallon of water with 200 grams of Dog Rocks. FOUR MONTH SUPPLY - 200 Gram units work for 2 months. This 2-pack set will last for four months. Simply replace the Dog Rock in your pets water dish every 2 months to prevent urine patches so your lawn remains lush and green.