The North Face
The Heated Hydration System, developed for the North Face Snowday and Flask hydration packs, is the first system to enable a user to carry water in below-freezing temperatures without freezing in the delivery tube.
The system will keep the water in a liquid state in 15-degree Fahrenheit conditions for up to 16 hours on a set of 4 AA batteries. A temperature sensor, nichrome heating wire, and a PIC microcontroller are used for active temperature control.
REM developed the electronics and firmware for the device and worked with The North Face and their oversees manufacturing partners to integrate the system into the pack.