Designed as an add-on pen for the Fontana Barn or as a free standing pen. Frame is made from ecoFLEX and carries a limited 10 year warranty against defect & deterioration. Door in pen for easy access in either mode of use. Wire in pen is galvanized after welding to minimize places where rust can begin. 20 gauge 1/2 " x 1/2 " wire keeps the critters out. No maintenance other than regular cleaning required. Will not go gray like inexpensive wood types will.