Radar Unit Model K55X 990097

Radar unit Model: K55X 990097, Ser No:  K55097004562, Patent: 4214243, FCC ID: FCC Data A-06-000011.  Classic K55 Radar unit.  I began using this radar unit back in 1988, thus it is at least 35 years old.  Not sure if it still works?  Unit comes with original case.  Being sold as is.  Once again, not sure if the unit still works.  Can't remember the last time we actually used it.  NO tuning forks.