Hi this should be a Sony WM-PSY02 Some infos here: https://www.hifiengine.com/manual_library/sony/wm-psy02.shtml
I don't think they're rare but they are towards the end of the cassette era, maybe 1999? I don't know anything about the Psyc Line but they used it on a lot of portables but I've never run across one.
Nice walkman , "PSYC" is a Sony product line from around 1998 below a page from a Sony book , tells pretty much anything about the line .