Made of high strength plastic. The base nests neatly into another Wolf Packs lid when stacked. Secures with the clip-to-close mechanism onto the same box base as the original Wolf Pack lid. Use in conjunction with Stratchits - by Front Runner as well asBlack Tie Down Rings - by Front Runner for a safe and secure storage solution. *Please Note: Wolf Packs with the Wolf Pack Hi-Lid will not fit into the Wolf Pack Drawer systems. The original lid will be needed for this application.