<P>Twistouts Permit Use Of Three Parallel Raceway Runs On Each Side. Base Has 1/2'' and 1'' Concentric Trade Size Kos and A 1 13/16'' (46MM) X 2 7/8'' (73MM) Rectangular Ko to Mount On A One-Gang In-Wall Outlet Box. Cover Accepts Devices With Mounting Screw Centers Of 2 3/4'', 3 1/2'', or 4 1/16'' (70MM, 89MM, or 104MM), and Canopy Fixtures No Larger Than 4 5/8'' (117MM) In Diameter. With 5736 Blank Cover, This Fitting Can Be Used As Junction Box, Pull Box, Etc. Note: Certified to Canadian Safety Standards