This toy includes two pieces that twist together. The treats are placed in the middle, and the difficulty level is determined by how tightly you twist the two pieces together. Small slits on the two pieces allow the dog to sniff what’s inside. The dog must figure out how to match the holes up and move the toy to get the treats to fall out. It comes in three different sizes: small, medium, and large. Those who have purchased this toy say: It’s pretty tough but not tough enough for aggressive chewers, who might chew through the toy to get the treats. Loading treats and cleaning up the toy is very easy. You can twist it loosely at first and then tighten it as the dog figures out how it works.