Removable Comfort-Fit multi-layer inner boot system; B-Tek Heat lightweight, 4-channel hollow-fibre insulation for high-loft breathability in a broad range of temperatures; Thermaplush soft, next-to-foot wicking layer for warmth; Form-fitting B-Tek Foam lining for comfort; Vaporized Aluminum Membrane for energy reflection and heat regulation; B-Tek Dry Waterproof Base; Ripstop nylon upper; Ankle-height with Velcro strap for easy fastening; Nylon locking snow collar to protect from the elements; Arctic Rubber base to provide lightweight flexibility, cold-resistance and resilience