These refueling kits are designed specifically for the Radium Engineering FCST. The FCST does not come standard with any of the parts in these kits. As described below, the Radium Engineering refueling kits come in a few different varieties.
NOTE: "Complete" refueling kits include a dump can, as shown in photos below.
COMPLETE REFUELING KIT, REMOTE MOUNT, STANDARD FILL
This option works for vehicles that require a standard filler mounted remotely from the fuel cell. The included flanged filler typically mounts to a body panel. A 1.5" fuel filler hose attaches to the provided Radium FCST mounted fill neck elbow. A proper vent kit secures directly to the 8AN vent that comes standard with the Radium FCST. 
The provided dump can features a large vent for faster filling than typical fuel jugs.