The TrolMaster Controller Cabinet Door without Knockout (SCC-D) is a solid front door, which converts the SCC-1 and SCC-3 cabinets into a solid/sealed enclosure to allow for the installation of the other TrolMaster controllers. With the new SCC-D blank replacement door, SCC pre-wired cabinets can now offer a professional installation for all TrolMaster main controllers. You can combine the SCC-1 or SCC-2 cabinets with the NEW SCC-D blank door. If you are installing one of the original TrolMaster main controllers HCS-1, NFS-1 or CDA-1, and wish to install it using one of the SCC cabinets, you can choose to mount the main controller on the front of the cabinet door, or you can hook it onto the DIN rails inside the SCC cabinet. Another option for larger installations using the Pro Controllers (HCS-2/NFS-2) is to add a second SCC-1 or SCC-2 cabinet and SCC-D door to allow more modules to be connected to the Pro Controllers in a secondary location.