Review on Yellow Colour Coded NERVOUS Dog Collars (S-M L-XL): Give Me Space and Prevent Accidents by Alerting Others to Your Dog in Advance by Jen Smith

This collar does the job. My rescue dog is very dog friendly but takes time to get used to people. This allows people to understand that they should not approach him and allow him to come to them on his own terms. The bright yellow and big black letters make it stand out and people are ready to ask questions and know what makes your dog tick. Nervous does not mean dangerous, but space. People are more understanding when my dog wears this collar and are less likely to believe he will turn fear into aggression.