I don't use them any more as there are some dubious ingredients in some of them and there have been cases of dogs being made very ill by some of the ones made in China and other Far Eastern countries. No way of telling what is in them. Not to mention bits breaking off and getting stuck or cutting gums etc.
Coco is not keen anyway, but I prefer to give her things like tripe stick (smelly) pizzles (revolting) Fish4Dogs treats (stinky), cow's ears - seeing a pattern here?
Carrots are great too - I freeze them for Coco and they last a bit longer that way and very soothing for sore teething gums