BOR 8 RODS Solid Internal Treatment. The use of solid borate rods such as the EPA registered BOR 8 Rod, DOT Rod, Cobra Rod or the Impel Rod has proven to be an effective way of protecting the internal area of wood poles and other timber 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. Many Southern Yellow Pine pole owners prefer solid rods over fumigants. Borates can travel up to 18” from the application hole. Always read and follow EPA label directions.