The premier overboot for high altitude mountaineering double boots and large volume single boots. Knee height and fully insulated throughout with nylon covered 4.7mm stretchy neoprene closed cell foam incorporating 2 layers of heat reflecting Titanium.  The insulation goes completely around and under your boot without having any gaps in the insulation.  This is glued together and stitched on the inside and outside surfaces, with no sewn through seams. Fits trim to the boot and leg. Compatible with most crampons. Heavy duty YKK® front zipper closure with snow flap. Thin rubber paint for added abrasion resistance in key areas.  Easy to repair and maintain.