I took a psychology class in 1973. Our professor was from England and had just come over.
He told us he was surprised that the department had a very new and expensive machine.
He passed it around the class and we all looked at it etc. I have no idea what it could do but it was about the size of medium sized book.
That was the first calculator I had ever seen. In 1975 I bought what at the time was a nice one. I think it cost $70 and was a Sears brand but was identical to a Rockwell brand so I am sure they just rebranded it.
Now I have purchased many calculators over the years and all the early lcd display ones have gone bad. I don’t think any of them last much more than 10 years. About a year ago I got that old Sears model out and it still works.
At first a few keys were balky but they began to work perfectly with just a little use. It takes 4 AA batteries. It has a bright green led display. I think it will work for many more years.
Something like a Nixie tube.