Flyball is not limited to the breed's size, as smaller dogs such as Patterdale Terriers, Jack Russell Terriers, Whippets and even miniature poodles, often compete with great success in mixed-breed teams (teams consisting of dogs of various sizes and breeds). Smaller dogs are often prized as the hurdle height is based on the height of the smallest dog in the team, commonly known as a "height dog". Their only limitation is whether they can trigger the release pad, and small dogs often have to fully jump on it to do so.