In this step in the assembly sequence of the Apogee Components 1/70th scale model of the Saturn 1B rocket, is where you'll be attaching the fin unit to the fuel tank sub-assembly. This step needs to be done before installing the SIV-B/Interstage; so don’t skip this step. The fit of the plastic transition over the fuel tank tubes is very snug. So before intallation, it will be necessary to remove any paint from inside the plastic transition.