Depends what you want from them, and your dog
These treats are fairly big (we ordered the medium) and very hard - they also smell really good!
Our Border Collie x Springer had one, and he ate the whole thing in less than two minutes. It didn't seem like he was swallowing large chunks, it seemed to crunch easily, but it didn't last long.
Our Border Terrier gnawed one for less than 10 mins (then got bored) and barely scratched the surface! He got the same milk bone later in the day and ate it all in about another 20 minutes.