Heating area: front foot / toes / foot soles, heating temperature: 40 – 65° C Heating duration: 3.5 – 8 hours, 3-level temperature control Breathable, sweat-regulating, quick-drying, elastic. Material: Coolmax Ski socks with Bluetooth, controllable via Savior Heat Intelligent Heating App. Package contents: heated socks, two 7.4V / 2200 mAh batteries, a dual charger with EU plug, a user manual.