Traex boxes have reinforced ribs on top and bottom add strength for extended life. Signature boxes have smooth interior bottom and ribbed exterior bottom. Stacking lugs prevent sticking together and allow for quicker drying. Reinforced handles. Made of high-density polyethylene. Approved for temperatures up to 180°F (82°C) and as low as -30°F (-34°C). Signature boxes have a hole in handle for easy drainage and a smooth interior bottom for easy clean up.