Date: Unknown, owner unknown

I am not sure during which years other than 1959 the strobotuner was in use, but presumably for quite a while. As befits a piece of equipment of the day, it is tube operated (see picture below).

What Conn said in 1959:
Simplified adaptation of Stroboconn - Every school should have one. Only low cost reliable visual tuning instrument made today! has 84 note (7 octave) range and has the same dependable accuracy as the large instrument. One extra operation involving the simple "click of the switch" for calibration produces the same precise pattern. One disc does the complete tuning operation by changing the note indicator. Shipping weight 16 lbs. Ready to use in standard outlet 110 volts 60 cycles, in durable metal case, complete with luggage handle.
...New attractive brown case
...Compact, neat - smaller than portable typewriter
...Opens ready for use with plug and microphone
...Visual tuning for any note on chromatic scale