Here we have an old LED calculator.
Toshiba BC-815.
Shows signs of it's long life. Someone glued the name tag on and leaked some glue.
Batteries had corrosion in past, but it is cleaned up and STILL WORKS !
If you have a cosmetically good one of these, great chance to get working innards for cheap.
Requires 4x AA batteries. (NOT INCLUDED)
Very vintage.