Wunder ball Refill Bag with 18 Balls (Comes with 6 Medium, 6 Large, 6 XL) in BOTH SOLIDS and SWIRLS Nearly Indestructible Introducing your pup's new favorite fetch toy - the WUNDERball! Made from 100% natural rubber and shaped by hand, our WUNDERball is nearly indestructible, cleans your dog's teeth, and provides a unique bounce pattern. With hundreds of glowing reviews and awards, the WUNDERball is sure to be a hit with your pup!