RADIAL/Duo is a blanking panel for the 500 series chassis/racks that provides two slots of protection for the rack against dust and other contaminants inside the case.
The MIDAS/MICROPHONE PREAMPLIFIER 502 V2 is a microphone preamplifier for the 500 Series modules. It provides a very desirable soft clipping characteristic while allowing a maximum signal level of +24 dBu without a pad.