What is your favorite chew toy for a power chewer?

The ultimate is the Souper Size Galileo Nylabone. It is about 7 inches long and 3 inches around. It has the slick surface. They are more attractive if you rough up the surface with sand paper or by rubbing it on a concrete floor. Another technique is to jam a Nylabone into a Kong creating what I call a twofer. The whole is greater than the sum of the parts.