The Merino Blend Heated Crew Length Socks feature a soft merino wool blend construction with heat under the toes for subtle, targeted warmth. The high-capacity battery provides between 4-16 hours of heat between charges (depending on the heat setting), and you have the added convenience of adjusting temperature right from the wireless remote control. For those who don't like above-the-calf socks and want long heat times, this is the sock for you.