Update: Fantastic balls! Until the end of May this year, we'd had the same two balls since 4 September 2016. During those 9 months they had been thrown, chased, caught, bounced on concrete surfaces, and chewed, yet they were still in 'as new' condition. In March I wrote "I don't know how the manufacturer makes money because they are truly virtually indestructible". And two months later I lost one! I threw it into the sea in Cornwall, for Polly to retrieve, and the tide took it away. We still have one of the originals, plus two new ones - ordered the night it was cast out to sea, because my ball maniac could not do without it (we'd left one at home 300 miles away). These balls are more at risk of loss than splitting or being chewed into pieces. Love them. Original Review: I have a ball-crazy Staffy. She constantly brings balls to me hoping I’ll play with her, and throws them around by herself if I won’t. She trashes a tennis ball in 2 minutes - pulling the fluffy fabric off, splitting it in half down the seam, and then chewing it to pieces. So tennis balls were banned, as were all dog balls bar the hard solid rubber ones….. but, although not a chewer normally, she does chew her way through them if left to play alone with one. Her teeth just sink into them, and I find little bits everywhere. The solid rubber balls are heavy, and I can't throw them far. They strain my neck, shoulder, and elbow, when I launch them with a thrower. Also, they are too hard and heavy for Polly to catch from a height or a distance, and I’m always afraid they’ll dislocate her jaw when catching them from a height. Her ‘friends’ have different Chuckit balls (whistlers, rebounders, and glow balls, which don’t float) and, whilst looking to buy her a set of these, I came across these Ultra balls - which looked far better for my dog. I read some of the 1300+ reviews for the Ultra balls, and I must say I was sceptical about them being virtually indestructible in a Staffy’s jaws. But, we’ve had them for two weeks now, played with them daily, and they are absolutely amazing - so far! Within minutes, on the day they arrived, I heard one of them squelching as she brought it back to me and my heart sank. I thought she had punctured it already, but then I discovered the secret of this amazing ball, and what makes it almost indestructible. There’s a tiny hole, in a groove, which allows the ball to squash between the teeth/jaws, pushing the air out, and preventing the teeth from penetrating its strong textured rubber. The squelching was Polly's slobber, in the hole. Amazing! I’m over the moon with these balls. Initially I thought they were rather expensive for a dog ball, but now I don’t begrudge a penny of their cost. The medium size seems to fit all types of standard sized launchers. I’ve owned dogs (as an adult) for over 40 years - three of which were Staffies - and I’ve never before been able to go out and leave my dog at home alone with a ball to occupy itself, without it being destroyed. In a short time, these balls will more than pay for themselves. I’m paranoid about losing them (as they are so bouncy) but, in the event that we do, I won’t hesitate to replace them with the same. They've given us so much pleasure already. IF MY REVIEW HAS BEEN HELPFUL, PLEASE CLICK ON THE ‘YES’ BUTTON, BELOW. THANK YOU.