Sophia BT-14 W Women's Basal Body Temperature Thermometer A barometer for fertility planning, dieting, and skin condition. With an alarm clock. Automatically records up to 210 days of data based on menstrual cycles and creates graphs, allowing you to confirm ovulation, estimate your period's due date, and easily mark potential pregnancies and health issues. The battery is dead, and I haven't been able to confirm its operation, but I was able to use it a year ago when I got pregnant. Since I got pregnant using this, perhaps it could be used as a good-luck charm or an auspicious item. There is no instruction manual, but you can find it online as shown in the second photo. - Battery: CR2032 - Brand: Sophia - Model Name: BT-14 W - Type: Women's Thermometer - Function: Basal Body Temperature Measurement