Gravity and city water fill with 1/2 inch MPT tank connection in a lockable hatch. Paintable UV stabilized plastic with 1/2 inch air vent for a fast fill. Includes installation screws, putty tape and PTFE tape. Cutout: 5-7/8 inch width x 4-3/4 inch height; OD: 7-5/8 inch width x 6-1/2 inch height.