The Hol-ee Roller X Extreme 5 is the relentless version of the Hol-ee Roller. This toy is made to endure even the most exuberant chomping. The Hol-ee Roller X is an all natural rubber dog toy with square cut outs that can be filled with treats or small toys. This is the toy for your toughest chewers. For medium, large and giant breeds.