This is a great, no nonsense app. Very simple to use.
My only recommendations to the developer, which would make it even better:
A) add a “back-space” button to enable erasing only one letter at a time. Otherwise, if you make a mistake, you need to erase everything and start again.
B) change to font on the ״ס״ to look less like a ״מ״ סופית.