Standard issue at the Marine Corps' Mountain Warfare Training Center. Have used them for years in the Marine Corps and purchased a set for myself -- Won't go to the field without them (Summer or Winter). They keep everything out. Wear them with shorts for 3 seasons, and pants in the winter. Used them on Mt. Rainier with AAI, on a NOLS expedition (Both offered OR Crocs as rental gear), and in the North Carolina mountains hiking, camping, and hunting. As another reviewer said: "Bombproof!"