The black boot is for wear in cold, wet climates (down to -20°F (-29°C)). The white boot is for wear in extreme cold, dry climates (down to -60°F (-51°C)).

The mountain combat boots are intended for use in rugged, mountainous terrain.

In 1988, the U.S. Army began a program to develop a new combat boot for dismounted soldiers and marines operating in cold and wet environments where the mean monthly temperature ranges between 14°F and 68°F (-10° and +20° C).The new Intermediate Cold Wet (ICW) Boot was designed to fill the protective void between the uninsulated U.S. Army Standard Combat Boot and the highly-insulated Extreme Cold Weather Vapor Barrier Boot.

Army footwear operational view.

The boot socks are anti-microbial, and contain a fiber that is coated in silver to combat bacteria growth that causes odor and stains.

The extreme cold weather mountaineering socks are intended for wear in sub-zero temperatures on rugged terrain.

The socks are seamless, stretch type, with a true or mock rib knit, elastic top, and a plain knit leg and foot with a terry or tuft stitch on the inside of the high heel, heel, sole, toe and ring toe.

The socks are seamless, stretch-type, with a true rib-knit top and a plain knit leg and foot with a terry or tuft stitch on the inside of the high heel, heel, sole, toe and ring toe.

The socks are natural-colored, seamless with a terry or tuft stitch to the inside of the entire sock and a top finished with a nonraveling welt, overedge stitching, or a rib stitch.