If you love dogs but hate those nasty brown burn patches he creates on your lawn, then Dog Rocks™ are the answer. Simply place the 200g pack contents in your pet's water bowl &, without affecting the p H of your dog's urine or medicating it in any way, they will eliminate the problem. Made from naturally occurring paramagnetic igneous rock, they are laboratory tested & 100% safe for your pet. Replace them after 2 months.