Used OV Watch with 3 sensors. Excellent condition. (Used 3 Cycles) Purchased in April 2008.
See below from OVwatch.com
OV-Watch® is worn on the woman's wrist while she sleeps. Women start wearing OV-Watch® on the 1st, 2nd, or 3rd day of their menstrual cycle and wear it through ovulation. It measures a woman's changes in her chloride ion levels that are secreted in perspiration every 30 minutes and records up to 12 readings per period. OV-Watch's patented technology detects the chloride ion surge and alerts the woman to FERTILE DAY 1, FERTILE DAY 2, FERTILE DAY 3, FERTILE DAY 4, OVULATION DAY 1, and the day after. It is the ONLY device of its kind that can give you the 4 days BEFORE ovulation.