Ovulation predictor kits (OPK's) are used to predict when ovulation is going to occur by detecting LH (lutenizing hormone) levels in your urine. LH rises significantly about 12-36 hours before ovulation.

A lot of women prefer Clear Plan easy ovulation predictor kits because they show clearer results than other brands, but this is not to say that other tests do not work as well. Remember that a high price doesn't always equal a higher quality- this also goes for pregnancy tests.

You can expect ovulation to occur within 12-36 hours after your positive result. I recommend having intercourse as soon as possible after your positive result. Your best chance of conceiving is by having intercourse within 2-3 days before the actual egg burst. Studies show that having intercourse on the day of ovulation gives a very small chance of conception. So timing intercourse before ovulation is the ideal thing to do to ensure that sperm are already present when the egg arrives.