Yeowww! Stinkies Catnip Sardines are packed full with 100% premium, organically grown catnip, no toy-grade catnip or filler. Cotton twill fabric is durable and will resist opening from your cat channeling their predator insticts to pounce, scratch, bite, and swat. If it does open, it is easy to refill and sew back up, any spilled catnip is perfectly safe for your cat. Cats over the age of 8 weeks receive the most enjoyment from catnip.