The design itself is enough to get one of these Nari Narwhal USB Heated Slippers for keeping your feet warm during those cold and chilly days. They are made of cozy cotton and polyester which snugs on to your feet and keeps them warm and comfortable. You have to use the detachable USB cable to plug these slippers to your Mac, PC or any other USB port to keep up with the warmth these slippers have to offer. The USB cable is 57” long which will enable you to stretch out your feet and yet stay warm. One size will fit most standard feet with the cute Narwhal design adding a fun element to it. Perfect for your winter days or any cold night you may come across.