Designed to accommodate the mounting of switches or other devices in masonry walls. Steel 3" L. x 2.5" W. x 2" D., 15.5 cu. in. Gangable design allows installer to build unlimited number of gangs to hold multiple devices in 4" block walls. Device ears are formed inside the box, preventing mortar from getting in the device holes. Forward mounted grounding provision allows for easy installation of grounding pigtail.