It is an easy-to-use home ovulation test, and is over 99% accurate at detecting the luteinizing hormone (LH) surge. The optical reader interprets your result and gives you a clear smiley face in the result window when the LH surge has been detected, identifying your 2 best days to try for a baby. For women whose cycles vary from month to month, it can be especially challenging to accurately detect the timing of the two most likely days to get pregnant. This kit will give you the highest chance of detecting your most fertile days whenever they occur.