Is Tempdrop safe? Do I need Wi-Fi or Bluetooth overnight?

Tempdrop is perfectly safe to wear and doesn't require Wi-Fi or Bluetooth to be active during the night. 

Tempdrop only transmits Bluetooth for a few seconds. First, for 30 seconds when it’s turned on, and again when you manually sync it to the app after wearing. Syncing takes around 10- 30 seconds per day. It uses a very low-energy Bluetooth signal (approximately 1000x less than a cell phone). 

While you sleep, the Tempdrop sensor is powered by a standard button battery and does not emit any wireless signals. There’s no need to keep Bluetooth or Wi-Fi on overnight.

Finally, Tempdrop is made from medical-grade materials and has FCC and CE certifications. The metal sensor is medical-grade stainless steel, which can contain trace amounts of nickel.