Model PTC306NC is a plastic cover made specifically to fit model 306NC feral cat transfer cage. Covers are great for calming caged feral cats because they feel safer and not as exposed. Transporting caged cats can be stressful for them, this cover will calm them down. Our plastic covers are made from .090 low density polyethylene that is UV protected. They are durable, easy to clean, and fold flat for easy storage.