Released in August 1989, the Macintosh SE FDHD was an updated edition of the Macintosh SE (released March 1987) supporting 1.44MB High Density (HD) floppies. SE units came configured to support either a 20MB or 40MB hard drive or dual floppy drives. It appears that this unit contains a hard drive, or at least doesn't have dual floppy drives. Production of the Macintosh SE FDHD was discontinued in October 1990, when the Macintosh Classic came out.
References: http://en.wikipedia.org/wiki/Macintosh_SE