Pyramex Ridgeline Cap Style Hard Hat Adapter is designed to fit cap style hard hats. This universal sizing fits on the brim of most hard hats and accommodates a variety of face shields (Pyramex S-1010 Clear Face Shield). Please note that safety glasses must be worn simultaneously, since a face shield is not rated as primary eye protection. Flying debris can get around the edges of the shield and injure your eye. The benefit of wearing a face shield is to stop particles from flying into your face while using a polishing wheel or grinder. Please note that there is a limit to what the shield will protect against, as pressure built up around the grinding wheels can project particles at great force. Please use caution when working with power tools.