The use of borate/copper rods such as the EPA registered Cobra Rod has proven to be an effective way of protecting the internal area of wood poles and other wood products. Borates diffuse within the cell structure of the wood and render the wood inhabitable to fungi and insects. For standing poles, solid rods are a wise choice especially in populated or environmentally sensitive areas. Borates can travel up to 18” from the application hole. Always read and follow EPA label directions.