Reel-to-reel: 2-Track Sarah Vaughan Billy Eckstine sing Irving Berlin. Reel Tape 15 ips Estate

Back in December 2019 I had sold several tapes of the same origin - a nice estate sale in San Francisco where the entire house was filled with collectable treasures of different kind. As I said back then the owner could not even live in that house because there was no room for beds, the kitchen was overloaded and it was hard to even freely walk in the house. Everything was overloaded with stuff. The guy was a photographer and collector - Ken Kogawa (not sure about the exact spelling of his last name)
Anyway, I have already sold almost all rock music tapes and now have only some vocalists and classical reel to reel tapes left. I'm listing a few vocalist tapes this month and I will list some classical tapes in June or July. Not sure if there's a demand in classical music but I will come with a list of composers perhaps next month.
Please note I could only test the tape on my 4 track consumer machine and it sounded perfectly just with unbalanced channels because 2 track recordings meant to be played on 2 track machines. But even with unbalanced channels it sounded pretty good.
Origin of the recording is unknown but it's not vinyl because I didn't hear any clicks or ticks that you would always hear on vinyl.
I'm sorry I can't test the tape in a real 2-track machine but again I could tell just from playing on my Akai gx-747 the sound was very good.
Might be a radio station copy? Or a backup copy? Or some kind of private collection? Hard to tell....
Please refer to photos for more details.