This is just my opinion but as a professional Dog trainer I have looked all over for a good collar for walking and riding bikes with my Pits and other dogs. I finally found it with the Illusion collar by Cesar Milan, Yes the dog whisperer sells these at a pretty reasonable price of 39.00 i can take all of my dogs which we have seven, with no pulling and no chance of getting away from me or my wife. A great tool.