Designed for use with nonmetallic sheathed cable in accordance with Article 370 of the 1990 National Electrical Code For Residential, Light Commercial, Manufactured Housing Safe non-conductive, non-metallic, PVC With captive nails Safe, non-metallic, non-conductive For new construction 2-1/4 inch deep 20 cubic inch box 6 internal clamps Fixtures spacing for 2-3/4 - 3-1/2 inch