Free toe warmers with your purchase! These soft and cozy socks feature an advanced carbon ceramic heating element , which gently warms the toes and soles of your feet, and is slim and unobtrusive for added comfort. They have three heat settings so that you can choose your ideal temperature, and will provide warmth for up to five hours . These socks are part of the Dual Fuel range by Warmawear, which provides you with extra heat options to make the most of your heated socks. Features Dual Fuel Technology allows you to have backup heat, extend the heating life of your socks and maximize the sock warmth by combining our disposable heat packs or toe warmers with the battery heating Advanced carbon ceramic infrared heating element distributes heat gently and evenly Socks stay warm for up to 5 hours , and require only 3x AA batteries each (not included) Discreet battery boxes with adjustable leg straps and flexible cables can be positioned over ski boots or wellies Easy-to-use remote control keychain - turn on/off, or switch between three heat settings Convenient on/off switch located on battery box - no need to remove the batteries to switch it on or off Machine washable (86Â°F gentle program) Warmth can reach temperature of up to 122Â°F Warm and comfortable , even when switched off Unisex design is ideal for both men and women Specifications Small/Medium - US: 5.5-8, EU: 38-42 (L9.5" x H14") Medium/Large - US: 8.5-11, EU: 42-46 (L10.5" x H16") 5% wool, 5% nylon, 5% spandex and 85% acrylic Machine washable (86Â°F gentle program) Requires 6x AA batteries (3 for each sock, not included) Heat Settings: High (Red) - lasts up to 2hrs between 89-122Â°F Medium (Orange) - lasts up to 3hrs between 89-113Â°F Low (Green) - lasts up to 5hrs between 89-104Â°F Dual Fuel The Dual Fuel system is an innovation from Warmawear that combines the power of disposable heat packs with our battery powered heating system for groundbreaking versatility . Extend the battery life of your socks , simply utilize the portable heat packs and their 122Â°F heat to save battery power for later Never get caught short with these sleek heat packs, use them as a brilliant non-electronic back up Maximize the heat you receive by combining the heating system with the disposable heat packs Use adhesive toe warmers on the inside of your socks for instant heat Our slim heat packs will stay warm for up to 6 hours and will help to deliver high levels of valuable heat when sealed into the utility pocket . Remote Control Simple keyfob remote control operation means you can switch the insoles on and off and change the heat setting without even taking your hands out of your pockets. Syncing the remote with the socks is a breeze. Simply press the battery box until the LED flashes red, and press the lock button once the light has switched off. Now, the socks and remote are synced! 3 Heat Settings The range of heat settings on these socks means you can choose how long you want the heat to last for, as well as the temperature! Easy to monitor with the colored light, you can change the heat setting depending how much warmth you need at the time. The warmth of these socks can reach as high as 122Â°F, and can last for up to 5 hours. Carbon Ceramic Heating Element The carbon ceramic heating element in these socks focuses soothing heat on the sole of the foot and the toes, improving blood flow to your extremities, and helping to protect your feet from the cold. Their gentle, consistent warmth can aid in the relief of Raynaud's Disease Discreet Battery Box Each sock comes with a discreet battery box which includes an adjustable leg strap and flexible cable. These features allow the box to be easily and discreetly positioned beneath your trouser leg, over your ski boots, or wherever is most convenient and comfortable. Each box also features an easily accessible switch which allows you to switch the heating element on, or to switch between the three heat settings, without the need to remove the batteries. The LED light on the box lights up to indicate that the heating element is turned on, and will turn red to indicate full power, or green to indicate our eco setting.