From the manufacturer Effective ovulation test kit* Did you know that one in two couples could be trying to conceive on the wrong days of the woman?s cycle**? And did you know that your basal body temperature only increases after ovulation, making it not much use to aid conception in that cycle? The Clearblue DIGITAL Ovulation Test detects the rise of the ovulation hormone LH 24-36 hours prior to ovulation and identifies the 2 best days to conceive in a given cycle. Making love during these 2 days gives you your best chance of conceiving. Clearblue Digital Ovulation Test