I bought this fun tunnel for play with my three dogs: a lab mix, a boston terrier, and a bluetick coonhound.  Within a few minutes, using treats and applause they were all going through the tunnel enjoying themselves immensely.  They range in age from almost one year to 7 years, and from about 65 pounds to barely 20 pounds.  It's perfect for all of them (although naturally I am not leaving it out all the time or the youngest might chew it to bits.)  You can see them on flickr.