I am trying to figure out how the 1.5" x 50 mm adapter (e.g., from BRS) is configured. I have a Reef Octopus skimmer (220 Internal), with a 50 mm outlet T. I want to put an elbow on the outlet to direct flow up instead of straight out horizontally. The hole is slightly larger than the spigot end of a street elbow, so I need an adapter to make things fit and stay together. What I need to know is whether the 50 mm side of the adapter is sized to fit into the 50 mm outlet hole of the T fitting (i.e., as a spigot fitting), or whether it is sized to receive 50 mm pipe (like a female slip fitting), in which case I will also need to get some 50 mm pipe to join the adapter to the T-fitting. Thanks.