Who doesn't know the situation when you're on operating and the pen doesn't want to write anymore or the pad is full or wet? With this app that's over! The smartphone is everywhere with you these days, so why not use it for the operation? Just enter the price list into the smartphone or import it from someone and let's go! The app can also take care of the tedious task of calculating the change. I would be very happy about ideas to improve the app or general feedback.