Tempdrop Body Thermometer Wearable Sensor Fertility Tracker Excellent preowned condition. I used this for a brief period several years ago and it has been sitting ever since. I just installed a brand mew battery to test that it is fully functioning. As far as I know, the actual sensor does NOT store any personal information. All of your fertility tracking and cycle/temperature information is connected to your USERNAME/email. Once you download the app and register your email, connecting via Bluetooth is easy. Comes with all items originally included: -storage box and bag -armband -two plastic housings -extra pins -battery removal tool -user guide