Brand New Sheppard & Greene Sleep Sack.  Measures 14" x 12" with four heavy duty cage hooks.  The Kozy Kage Ferret Sleep Sack is made of durable,washable fabric and is lined with heavyweight Sherpa lambs wool.   Attach metal hooks to the wire of the cage ceiling or walls and the sleep sack acts like a hammock or hanging sleeping bag.   Ferrets love to tunnel inside the sack.