CLEARBLUE Digital Ovulation Test Identify the 2 most fertile days Medical device 10 test sticks During each menstrual cycle, the days on which conception can occur are limited, so for those who want to have a baby it is important to have sexual intercourse on those days. The Clearblue Digital Ovulation Test detects the rise (peak) of luteinizing hormone (LH) in your urine. This peak occurs approximately 24 to 36 hours before the ovaries release an egg, a process known as ovulation. Fertility is highest on the day the LH surge is detected and the following day. The 2 most fertile days begin when the Clearblue DIGITAL ovulation test detects the LH surge. Having sexual intercourse within the next 48 hours will give you the greatest chance of getting pregnant. Accuracy greater than 99%. Easy to use Reusable reader and 10 Clearblue ovulation test sticks included