The Clearblue Digital Ovulation Test (Prueba de Ovulacion Digital) identifies your 2 best days to get pregnant. The simple urine ovulation test 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 digital display when the LH surge has been detected, so you know this day and the following day are your 2 best days to try for a baby. For women whose cycles are variable, it can be especially challenging to accurately detect the timing of the two best days to get pregnant. A 20 count test kit will give you a higher chance of detecting your most fertile days.