(under subclass 228.1) Device wherein the surface of the step structure intended to be engaged by a climber comprises a frictional means (e.g., nonslip projections, rough surface, etc.) to prevent a foot or hand of the climber from slipping.
SEE OR SEARCH CLASS
52, Static Structures (e.g., Buildings),
177+, for a residual building component with a wear decreasing or friction increasing traffic carrying surface.
