My grandfather had this old Casio calculator that functioned as both a clock and a calculator.
It has 3 modes: Clock, Musical, Calculator
In the top right you can see the mode selector. I'll go into detail about every mode and what it does.

Clock mode (Top), It has:
- 2 Alarms (the second alarm would reset after triggering once)
- Timer
- Stopwatch
- Time & Date (If you look closely in the first picture, you'll see that it also displays which day of the week it currently is)
The Timer and both Alarms have their own beeping sound

Pretty cool for a calculator but the Music part is where it gets really interesting
I forgot to mention this at the start of the thread but the ML part of the name means "melody"

Music mode (Middle), Is kind of in between Clock mode and Calculator mode (pun unintended)
If you had a timer or an alarm set and it went off during music mode it would play some music
More detail about it in the second image I have attached to the thread

Additionally, Pressing on the timer or any of the alarms would also trigger the sound to play. Pressing again would stop playing the sound
Pressing any key would make a beeping sound except for the aforementioned timer and alarms and the numbers which would play a different sound depending on which number you pressed
the higher the number the higher the pitch
if you type in a random combination of numbers and press the solve key it would play the sound of all the numbers one after the other

AND finally the calculator mode aaaand it's just the music mode without the music.
As for the leather case it has a small pocket to put in stuff as you can see in the third picture. Although I am not really sure what you would put in such a small space.
This calculator is made in Japan but I don't think it's really that important to mention
I also looked for a Casio ML-80 which just looks like the one I have but orange
And that's the end of the thread, thanks for reading.

https://boyet.com/blog/a-musical-calculator-casio-ml-81/
here's a link to the page I took the second screenshot from