Designed to meet the spacing requirements of the 1990 National Electrical Code, article 300-4-(d). Allows installation of multiple NM cables on one side of a 2x4. Accepts a wide range of flat NM cables, from 1 number 14-2 AWG to 1 number 10-2 AWG. Also accepts round cables up to .30" diameter. Spaces cables to center of standard 2x4. Reduce potential heating that could occur if cables are stacked under a single fastening device. Dresses wires for professional look in exposed areas, such as panel boxes. Easy installation - cables snap in for positive lock. Simplifies cable identification. Made from reclaimed plastic.