Wikipedia
Skatestopper
Skatestopper is the brand-name of a skate-deterrent device placed on urban terrain features such as benches and hand rails to discourage skating on the surface where they have been installed. The name Skatestopper is a registered trademark of Intellicept of El Cajon, California, United States. Skatestoppers are designed to be used in conjunction with warning signs and are not intended to eliminate the activities of skateboarding or inline skating. In some skateboarding circles Skatestopper has become a genericized trademark referring to any purposely installed device designed to discourage skateboarding.