our 42# Brit and 32# English Setter had the large size finished within 15". The Brit won, as always. He's a more aggressive chewer. This is my first try at Boodas in about 5 years. I used to buy them in the store for our previous dogs long ago and was always very happy with them. These have the little nubs on them, which slowed the Brit down, but still don't last (like the old ones which were thicker) did. Overall, a good product-wheat free is good.