Replacement Astoria CMA Espresso machine shower plates, from Coffee Spares Direct. Also refered to as Group screen, Dispersion screen, or shower head. These are located on the group head. It is important to make sure these are not damaged or have debris in to provide an even flow through to your espresso grinds. Usually secured with one screw centrally mounted, caution must be taken when removing as the screw can be difficult to loosen.