Our equipment weighs 1,200 lbs and takes 3-4 inch cores or plugs from even the hardest of soil. YOU are responsible for marking all Sprinkler heads, control boxes, wireless DOG fenses, other low voltage lines, city water valves and any other items, obstacles, equipment, devices, etc. that could be damaged while we aerate. Again, It is YOUR responsibility to identify and YOU are ultimately responsible for repair and damage.