The CASY303 covers three module spaces in a CASY chassis and is a universal base for two 45 x 45 mm standard sized products such as matrix control panels, volume controllers, connection plates, .... The cover frame includes four security tabs that can slide in the top and bottom of the frame. These tabs will ensue a firm fixation of the installed connection plate while plugging and unplugging connectors. The module plate will ensure a flush mount installation in to any CASY configuration.