Description: 78mm for Gravity Water Fill Hatch Inlet: Made of durable plastic shell and stainless steel inner core, aging resistance, good toughness, not easy to crack. With Locking Keys: Lockable, with 2 keys to prevent others from opening the filling port. Silicone Dustproof Cover: Designed with a dustproof cover, clean and convenient. 9mm Water Tank Vent: Diameter 9mm air vent, reverse venting design prevent the formation of vacuum water tank, easily adding water. Simple Screw Installation:It can be used on a variety of models, such as RV ,Camper ,Trailer, , Cars. Specification: Material: Plastic + Stainless Core for Aperture Diameter: Approx. 78mm/3 inch (hole) Inner diameter of the interface: φ 32mm /1.26 inch Outer diameter of interface :φ38mm/1.50 inch Air vent size :φ9mm/0.35 inch Product Size: 118x11mm / 4.65x0.43 inch Packing size :12x12x12cm/ 0.47x0.47x0.47 inch Suitable for casement door thickness: about 30-40mm/ 1.18-1.57 inch Package Includes: 1 Piece for Gravity Water Inlet 4 Pieces Screws 2 Pieces Locking Keys Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on-line shopping!