19 I mentioned ORB ports when discussing the filter. The fuel cell outlet, filter, regulator, and fuel log all use these (ORB is an abbreviation for O-ring Boss). The components have a groove around the port, for which fittings such as these, equipped with O-rings, are required, making a secure seal. On the left is a -6 fitting for the regulator, with the larger fitting on the right required for the fuel log. A similarly O-ring-equipped blanking plug is used at the other end of the log on my system.