I purchased this toy for my last dog and filled it up with tennis balls, which she would remove over time. It lasted a couple years before it started breaking down/disintegrating due to the elements (sun, water, tugs).
I purchased two more for two different dogs and put a few tennis balls inside, as well as some tied-off socks filled with treats. The treats came out easily enough, but one dog strategized that the easiest way to get the balls out was to make the holes bigger - and so he did. If you have a determined dog willing to do whatever it takes to accomplish his goal AND want the toy to stay generally intact, I'd find something stronger. I'm guessing that it also wouldn't hold up well to repetitive games of tug with 2+ strong, determined players.
Things that I do like about the ball are that it is a soft rubber so it's not only easy on wood floors, it's also quiet. I think it fits 8-11 tennis balls inside, which is a great, self-entertaining challenge for some dogs.

If you are looking for a durable chew toy for anything but a very tiny dog, this isn't the toy for that. However, if you are looking for a fun toy that you can use to interact with your dog, this might be a good choice. I have a 150 pound Saint Bernard and we have 2 of the jumbo Hol-ee Rollers that we have been playing with for over a year. They are still in great condition and we play with them several times every day. I actually am planning to order 1 or 2 more because occasionally we 'lose' one somewhere in the yard for a couple days before it reappears. My Saint can be a wild man and he is very mouthy when he plays. So, after 4 ripped shirts and more scratches and bite marks than I can recall from his teeth, I got the idea for him to carry a toy when we play in the yard. This is perfect! We have every kind of ball you can buy and this is definitely his favorite. I think it must be more comfortable to carry and it is easy to pick up when running past and carry around. He usually carries one and I walk around with him and either throw or kick another. He chases the one I threw or kicked and waits for me to catch up to kick it again. Sometimes, he decides to trade and drops the one he has and picks up the other. I can't even guess how many hours we have spent playing with these two toys! Also, this toy doesn't hurt your foot when you kick it even if you don't have shoes on and you don't have to worry if your dog accidentally runs into the path of it and it bonks him on the head. Plus, you can kick it across the grass or kick it up in the air and over obstacles like bushes or branches, etc. It goes pretty far without much effort. So much fun! Also, you can put treats and toys inside of it to make it more interesting, but we have never done that because he loves it the way it is.

My pup loves these things. Ordered the largest size and the smallest size and combined them. My cavalier goes crazy trying to get the little one out. Worth every penny.

I was searching for a great toy for my pit bull (8month olds) and decided on this toy. He is a chewer, and destroys anything he can rip apart. I went with the green x-large size ball, and he just loves it. It has some weight to it, and he still picks it up and runs around with it with ease. I try to only let him play with it while supervised, and so far it is still in one piece!.. after a month now. When you throw it, it rolls does not bounce. Hope this helps.

Our dog is spoiled..she has many many toys/balls from JW Pet Company. She has this type of ball in the medium and larger sizes. However, this one is quite small so we wondered if it would work out or not. The good news is she loves it...she throws it back to us quite easily because it is so small and lightweight. Bottom line, we are glad we purchase THREE of these. That way she can always find one..especially if one gets under the bed. Thank you JW..as always..we are very pleased with all the JW products we have purchased.