The Chuckit!? Crunch Duo Tug? combines classic Chuckit! Balls with a crackling, crunchy sound your dog will love during games of toss and tug! Designed to satisfy your dog's instinctual curiosity for sounds, the Crunch Duo Tug has a proprietary sound method that is safely contained inside the balls and will not break down with use. The Crunch Duo Tug features two Super Crunch Balls made from durable TPR on each end that are connected with a durable super-strong rope for tugging & twisting fun! Makes playtime fun and interactive.