Olympia CD 400 Calculator
It appears to be a follow-on to the ICR-412, also found on this site.
Like the ICR-412, The circuit boards carry the Japanese-language “National” logo indicating that the machine was produced by Matsushita as an OEM for Olympia.
The the CD 400 is very similar to the Panasonic 1200 although the Panasonic appears to have shift register memory rather then an acoustic delay line. National and Panasonic were both brand names used by Matsushita and it appears that very similar machies were made by Matsushita and then sold under a number of brands and arrangements.
The CD 400 is a basic 4-function, one memory machine and would soon be rendered obsolete by the emergence of small LSI-based calculators.