Made by FAWO of Germany. If it's not of sufficient quality, they don't make the shelves. LOCKING WATER INLET FILLER CAP. Sturdy ABS plastic locking filler available in either white or black. Positive key locking similar to a car fuel cap.
eBay
A Set Motorhome Water Tank Cover Water Inlet Adapter with Water Pipe Joint High Quality RV Water Tank Cap Filling Accessories
Aliexpress UK
eBay
Marine Boat Hardware Deck Filler 38/50mm 316 Stainless Steel Key Cap Filler Water Waste Diesel Gas Fuel Deck Filler 1.5" and 2"
Aliexpress UK
RHEINLAND Water Filler Inlet with Quick Connection. The Rhineland water filling cap fits in place of your locking water cap during filling. This cap will not fit Fiamma inlets . No leaks whilst refilling water tanks.
eBay
Marine Deck Filler 38mm 50mm Marine Boat RV Hardware Flip-top Filler Neck 1.5" 2" Water Waste Diesel Gas Fuel Deck Filler Cap
Aliexpress UK
Complete with pre installed Zadi lock and 2 keys. (If you install your own lock you will need the special Zadi key).
eBay
45 Degree 316 Stainless Steel Deck Filler Key Cap GAS DIESEL FUEL WASTE WATER 38mm 50mm Deck Filler Caps for Marine Boat
Aliexpress UK
Constructed from premium-grade, weather-resistant materials, this set is built to withstand the toughest outdoor conditions. Our filler cap features rubber seal to avoid any leak and a 10mm air vent for smooth filling.
eBay
316 Stainless Steel 45 Degree Deck Filler Key Cap GAS DIESEL FUEL WASTE WATER 38mm 50mm Deck Filler Caps for Marine Boat
Aliexpress UK
It has two water release holes in the top to warn of over filling or allow for over fill to be released. The food safe water hose can be fitted if required. This unit is unique to others. It has a tapered guide at one end which avoids issues when feeding the tube into restricted filler hoes like the one fitted to many Roller Team water units.
eBay
Gravity Freshwater Inlet Lockable Leakproof Water Filler with 2 Keys for RV Motorhome RV Parts Gravity Water Inlet
Aliexpress UK
Complete with pre installed Zadi lock and 2 keys. (If you install your own lock you will need the special Zadi key).
eBay
Water Tanks Filler Water Fill Caravans Filler Neck Trailer Tanks Caps 38mm
Aliexpress UK
Complete with pre installed Zadi lock and 2 keys. (If you install your own lock you will need the special Zadi key).
eBay
1pcs 3D Printed Caravan Toilet Flush Filler Funnel Caravan Motorhome Toilet Flush Filler Funnel Header Tank Filler Fit Caravan
Aliexpress UK