High Country Plastics BEAR BOX is a heavy duty pack box made to withstand years of back country packing. It is a certified Bear-Resistant Container designed with durability and performance in every aspect. The sides are curved to fit comfortably on your pack horse or mule. Each box comes with blended poly-nylon straps for extra strength in attaching the boxes to your pack frame and easy length adjustment. The lid has eight 5/16″ wing bolts to secure it to the box and keep animals out.