Product Description: LH (luteinizing hormone) is a hormone which triggers ovulation. Approximately 24 to 36 hours prior to ovulation. The Presense Ovulation Test detect this hormone through secretion in the urine. The LH increase signals the start of your 2 most fertile days for conception. How to use: You have to start testing on the day 13 from the beginning of your period Hold the absorbent tip in your urine stream for at least 10 seconds or collect your urine into a clean & dry container dip for 5 seconds in container. Re-cap the device for hygiene reasons and wait 3 minutes Caution & Warnings: Do not perform the test with the 1st morning urine as the concentration may be too high and this may distort the result.