Bamboo Shield - 25 Foot Long x 30 inch x 80mil Bamboo Root Barrier/Water Barrier Controls growth of bamboo by limiting rhizome (root) expansion. Made in the USA from High Density Polyethylene (HDPE). 80 mil material thickness that provides 155 pound-force puncture resistance Superior to metals because it will not rust and easier to install. Protective side is chrome rolled to provide a better rhizome deflection surface. Shiny side of the barrier goes towards the bamboo. Slightly angle barrier (5-10) where the bottom is closer to the bamboo. A minimum of 2 should be left exposed above the soil level. Material tends to remain coiled after shipping. Expanding it out in the sun for a few hours can make installation easier. Locate and confirm the location of all underground utility lines and structures prior to digging and use caution.