ArcticShield Boot Insulators in Realtree Xtra Camouflage Pattern are windproof, water resistant, lightweight, and easy to pack. They are composed of a polyester outer shell and liner and posses Retain heat retention technology. This technology varies the heat level to give you warmth where you need it most, while still avoiding bulkiness and allowing for easy movement. Strategically located throughout the garment, the Retain technology captures greater than 90% of body heat, and maintains the 90% heat for a long period of time. Boot insulators provide easy access with an open YKK locking zipper and adjustable drawcord.