3M Thinsulate is term used a lot in this article because the majority of the gloves use this material. Thinsulate, as you likely guessed, is a thin (microfiber) material made by 3M. The thin microfibers are super efficient at trapping warm air from the body in the gloves while also allowing the hands to breathe. Sweat build up in the gloves is deterred by the breathability of the gloves from the Thinsulate.