irregularly shaped with over all dim 14.687 inch lg x 12.062 inch w.irregularly shaped aperture 4.312 inch lg x 3.000 inch w.one open end slot 5.062 inch w x 7.312 inch lg with 2.531 inch radius on closed end.fifteen (15) each bolt holes irregularly spaced.two holes 0.531 inch dia.thirteen holes 0.437 inch dia.