The hopper is a 3/8" thick wall of HDPE UV protected plastic that will not rot, rust or leak! The hopper has built in channels that the legs fit into. Optional adjustable hardware components allow you to adjust the height for conversion from protein feeding in the summer to automatic timer feeding in the fall. The feeder is built to be rock solid, water proof, and to resist condensation. The lid is designed with a loose fit to allow proper ventilation for protein pellets. The lid system locks the lid down, but allows the hopper to achieve ambient temperature quicker than steel or fiberglass. This helps keep the feed fresh and as free as possible from moisture.