Designed as an add-on pen for the Jumbo Fontana Barn or as a free standing pen. For use as a free standing pen, the kit includes an extra back panel. 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 stainless steel to eliminate the possibility of rusting when exposed to the elements. 20 gauge ½" x ½" wire keeps the critters out. No maintenance other than regular cleaning required. Will not go gray like inexpensive wood types will.