Ovacue Vaginal Sensor  $100.00  While the vaginal sensor is not required for predicting ovulation, most of our customers elect to purchase one. If you are uncertain about whether you are ovulating, the vaginal sensor will give you a clear answer. It also gives you the added confidence that the OvaCue is indeed predicting your date of ovulation accurately. Finally, by confirming ovulation it clearly marks the end of your fertile period. If you choose not to order the vaginal sensor now, you can always purchase it later. :   Quantity: