Besides the BASE installation there are also packages. Each package contains one or more “OPTs” 4.1 which can be installed in addition to the base installation. Some of the OPTs are part of the BASE package, other have to be downloaded separately. The download site (http://www.fli4l.de/en/download/stable-version/) gives an overview over the packages provided by the fli4l team, the OPT database (http://extern.fli4l.de/fli4l_opt-db3/) contains packages offered by other authors. In the following, we describe the packages supplied by the fli4l team.