JR Products Polar 3-1/2"RO White Round Lockable Electrical Hatch Access Door 370-2-A 19-0198

3-1/2 Inch Cutout Dimension, 4-1/2 Inch Height x 2-3/8 Inch Width. It accepts 30A/ 50A cord. It comes with a snap lock feature to keep it securely closed while traveling. Replaces any round hatch up to 4-1/2 Inch.