CASIO fx-4100P Scientific Calculator from 1991

[Chasfield]

I have an FX7000G from Casio's rubber membrane keyboard era. I think they subsequently regretted this cost saving design rationalisation. I seem to remember Casio, and their competitors, being at pains to point out the presence of hard plastic keys in the box artwork of subsequent products.

All the same, they were well built and durable calculators.