Sturdier than other round electric cable hatches. The outside collar is wider to cover up any pre-existing screw holes. The hinge is extra heavy duty. UV and impact resistant, chemically resistant to road salts and acids, paintable. Vermin door accepts a 30 or 50 Amp cord. Replaces any round hatch up to 4-1/2". Cut Out Dimension: 3-1/2" Dia. Outside Dimension: 5-1/8" Dia.