This app was mentioned in 2 comments, with an average of 6.50 upvotes
The president of the company I work for has one of these on her desk.
So that this doesn't become another debate over survivorship bias, I will point out that they are still sold.
HP also sells an official app version of this calculator but clone apps are out there as well.
If you have an Andorid device , you can get the official emulator for 14.99 USD.