JR Products Polar White 3-1/2"RO Rectangular Lockable Cable Hatch Access Door 541-2-A 19-0188

3-1/2 Inch Cutout Dimension, 5-1/8 Inch Height x 2-3/8 Inch Width. It accepts up to 30A/ 50A cords & comes with a snap lock feature to keep it securely closed. Sturdier than other round electric cable hatches.