The Home Audiometer Hearing Test Windows software turns your PC into a machine you can use to test your hearing through a standard sound card. While this is clearly not as accurate as a professional audiometer, it can give a good indication if there is a hearing problem or not. (The accuracy is 10-15 dB compared to 5dB accuracy of a professional meter over a total hearing range of 70dB, so worse by a factor of 2-3.) The unlock key code is valid for all versions of the software, including future updates.