A permanent fitting at the top of the fill pipe [2]of an underground storage tank [3] that allows for a delivery hose [4] to be quickly connected to the fill pipe in a liquid tight manner.
See also Swivel adapter [5], Fill cap [6], PEI/RP900 [7].
Links
[1] https://testing.pei.org/wiki/fill-adapter
[2] https://testing.pei.org/node/1114
[3] https://testing.pei.org/node/300
[4] https://testing.pei.org/node/334
[5] https://testing.pei.org/node/1111
[6] https://testing.pei.org/node/1112
[7] https://testing.pei.org/node/317