Manufacturer: Niikura Kogyo  Co., Ltd
Model: 37AF(K)-50 to 100

NC No. 37AF Filling Cap CAP, NC No. 37AFK Filling Cap with Locking Device Models

Function
This product prevents impurities like hose hardware and dust from entering the clear water tank during fresh water loading, keeping the tank clean.
The 65 mm hose screw, mainly for drinking water loading, follows the American fire hose design.
This serves as a supply port for fuel and oil tanks and also functions as a gas concentration measurement port for the tank.