TrolMaster Controller Cabinet Door without Pre-cut Opening (SCC-D) is a solid front door, which converts the SCC-1 and SCC-3 cabinets into a solid/sealed enclosure to allow the other TrolMaster Controllers to be installed. With the NEW SCC-D blank replacement door, the SCC pre-wired cabinets are now able to provide a professional installation for ALL of the main TrolMaster controllers. You can combine the SCC-1 or SCC-2 cabinets, with the NEW SCC-D solid door. If you are installing one of the original HCS-1, NFS-1 or CDA-1 TrolMaster main controllers, and you want to install it using one of the SCC Cabinets, you can either choose to mount the main controller on the front of the enclosure door, or it can be clipped into the DIN rails inside the SCC cabinet. Another option for larger installs that are 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. *NOTE: The SCC-D is compatible with the SCC-1 and SCC-3 cabinets.