The Grüezi bag 'Feater-The Feet Heater' was extensively checked for its functions by 'WildHikes TV'. You can see in the video what the heatable, waist-high additional bag, which fits in every sleeping bag, is suitable for: WildHikesTV -Video from November 04, 2018 - Feater - The Feet Heater The heating element installed in the foot area can be operated with a standard power bank via a USB interface. Ice feet don't stand a chance anymore! Fulfill your dream of an extra portion of warmth with the 'Feater - The Feet Heater' from Grüezi bag.