The WT1B wireless thermostats are the first on the market to be equipped with a built-in rechargeable LiPo battery. When the low battery symbol appears on the display, you can simply connect the thermostat to power via the USB-C connector, similar to charging smartphones. This avoids the worry of replacing batteries or annual maintenance. The battery will charge in about 10 hours. Charging via USB-C is not only easy, it's also environmentally friendly and sustainable, and helps you keep costs down.