This is a basal body thermometer. I used it to measure my basal body temperature while trying to conceive. Measuring at the same time every day makes it easier to manage your physical condition. ✔ Measures correctly ✔ Cleaned and disinfected ✔ Simple and easy-to-use design I took good care of it, but I no longer have a need for it, so I'm selling it. I hope it can be useful for someone who needs it. Instant purchase is welcome ◎ Approximately 10-second quick measurement You can also manage your temperature and cycle on your iPhone/Android smartphone Medical device certification (approval) number: 223AGBZX00261A01 Size: 3.9 x 1.6 x 10.3 cm Power supply: DC3V