The SANDIA Aerospace MARC Series of remote accessory cards provide the installer with a wide variety of interface circuits needed to integrate today's avionics systems. The MARC70 units can be housed in an SRU 1 single enclosure or can be installed in either the SRU 5 or SRU 10 multi-card enclosures. The SRU 5 will hold up to 5 interface modules while the SRU 10 can hold up to 10 modules. The MARC70 units are PMA'd and certified to 55 thousand feet. Regulator/Dimming Board.